SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 255 AM MST WED MAR 15 2000 ...POTENTIAL FOR SIGNIFICANT SNOWFALL IN SOUTHEAST CO MOUNTAINS AND PLAINS MID AFTERNOON THROUGH TONIGHT... MODEL DISC: WHAT A DIFFERENCE A MODEL RUN MAKES! TIMING OF THE NEXT WEATHER EVENT HAS VERY GOOD RUN-TO-RUN CONTINUITY. HOWEVER...THERE HAS BEEN A SIGNIFICANT MODEL RUN SOLUTION CHANGE ON THE POSITION OF THE NEXT POTENTIAL WINTER STORM. CURRENT SHORT RANGE MODELS HAVE A FURTHER WEST AND SOUTH SOLUTION ON THE UPPER LEVEL STORM. BY THU AM...ETA IS MUCH FURTHER SOUTH IN NM WHILE AVN/NGM IS FURTHER NORTH ACROSS NORTHEASTERN NM. ETA PROBABLY TOO LIGHT IN THE OVERALL QUANTITY OF DEEP MOISTURE. AVN/NGM PRETTY MOIST LATER ON TNGT. GENERALLY...HAVE USED A PIECEMEAL MODEL SOLUTION ON WEATHER TRENDS. TDA: CURRENT WATER VAPOR IMAGERY SHOWED NEXT SYSTEM DRIVING THROUGH ID. 08Z/15 SURFACE ANALYSIS HAS FIRST COLD FRONT JUST GETTING INTO NORTHERN CO. SO FAR...HIGH CLOUD COVER AND WESTERLY SURFACE WINDS HAVE KEPT TEMPS UP IN THE UPPER 30S TO NEAR 50. WILL LOOK FOR FIRST COLD FRONT TO SLIDE SOUTHWARD AND PUSH UP AGAINST EASTERN FRONT RANGE BY THIS AFTERNOON. LATEST RUC HAS VIGOROUS MID-LEVEL SHORTWAVE TROUGH ENTERING NORTHWESTERN CO...WHICH WAS DEPICTED BY YESTERDAY'S MODEL RUNS. HOPE IT DOESN'T STAY ON A FURTHER NORTH TRACK...WHICH WOULD ALTER FORECAST. ULJ STILL DIGGING...SO MAY HAVE FURTHER DEEPENING OF SYSTEM. SHORTWAVE PROGGED TO PUSH INTO EASTERN UT/WESTERN CO BY 00Z/16 THU. 700MB LOW PROGGED TO DEVELOP IN CENTRAL CO BY 18Z/15 WED THAN MIGRATE SOUTHWARD. INITIALLY ACROSS SOUTHEAST CO MOUNTAINS AND PLAINS...LOW LEVEL TROP PROGGED TO BE RELATIVELY DRY...BUT SHOULD START TO MOISTEN UP BY LATE THIS AFTERNOON AS 30S SURFACE DEW POINTS ADVECTING WESTWARD. SIGNIFICANT AND DEEPENING UPSLOPE FLOW NOT ANTICIPATED UNTIL MID/LATE AFTERNOON. CLOUDS SHOULD BE LOWERING AND THICKENING ACROSS THE SOUTHEAST CO MOUNTAINS AND PLAINS. MOST OF THE PRECIPITATION WILL BE IN NORTHEASTERN CO THIS AFTERNOON THEN EXPAND SOUTHWARD LATER THIS AFTERNOON AND TNGT. WITH 700-500MB STATIC STABILITIES BECOMING MORE UNSTABLE...7-9 C/KM... SCATTERED SHOWERY PRECIPITATION LOOKS GOOD. 850-700MB THICKNESS STILL SUGGEST MAINLY LIQUID FOR THE PLAINS...EXCEPT MAYBE A MIX OR CHANGEOVER IN 71/72 AND SOUTHEAST MOUNTAINS. WILL NEED TO TWEAK POPS UP A BIT...ESPECIALLY IN 67/71/72. FOR SOUTHWEST/CENTRAL MOUNTAINS AND SAN LUIS VALLEY...LOOKS LIKE THE BEST COVERAGE IS FOR SAWATCH RANGE AND SHOULD REMAIN BELOW ADVISORY TYPE NUMBERS WITH UPSLOPE COMPONENT WEAKENING...COULDN'T RULE OUT LOCALLY HIGHER AMOUNTS IN HEAVIER SNOW SHOWERS. MAY NEED TO TWEAK TEMPS DOWN IN THE PLAINS GIVEN A FAVORED COOLER EASTERLY SURFACE WIND AND CLOUD COVER THIS AFTERNOON. TNGT: POTENTIAL FOR SIGNIFICANT SNOWFALL FOR SOUTHEAST MOUNTAINS AND PLAINS. IN RESPONSE TO VIGOROUS MID-LEVEL SHORTWAVE TROUGH DIVING INTO CENTRAL NM AND SURFACE CYCLOGENESIS IN SOUTHEAST NM/WEST CENTRAL TX...UPSLOPE FLOW TO DEEPEN AND STRENGTHEN IN EASTERN CO. THIS IS A TOTAL DIFFERENT SOLUTION THAN DEPICTED BY MODELS YESTERDAY. ANY FURTHER CHANGES COULD SIGNIFICANTLY ALTER SNOW AMOUNTS. MODERATE LARGE SCALE ASCENT...PER LAYER TOTAL Q(QS+QN)...AND A NEARLY ORTHOGONAL OROGRAPHIC FLOW ACROSS THE SOUTHEAST MOUNTAINS AND PLAINS SHOULD BE MAXED OUT. WITH SUCH INTENSE LIFT...WOULD BELIEVE STRONG DIABATIC COOLING WILL TAKE PLACE FOR PRECIPITATION CHANGEOVER IN THE PLAINS AND MOUNTAINS. 700MB TEMPS PROGGED TO DROP TO -8 TO -10 C WITH 070-090/20-30KTS WIND BY 06Z/16 THU. SNOW MODEL USUALLY UNDERESTIMATES ACTUAL SNOW EVENT FOR SOUTHEAST MOUNTAINS. IF EVERYTHING COMES TOGETHER...COULD SEE 8+ INCHES FOR SOUTHEAST MOUNTAINS WITH CUCHARA AND EAST FACING SLOPES OF WET MOUNTAINS POSSIBLY RECEIVING HIGHER AMOUNTS. IF DIABATIC COOLING WILL BE AS STRONG AS MODELS PREDICT...COULD SEE FAIRLY SIGNIFICANT SNOWFALL FOR THE PLAINS AND FOOTHILLS. ALL MODELS SNOW ALGORITHMS PREDICTING 6+ INCHES FOR THE PLAINS. JUST DEPENDS ON CHANGEOVER. WITH THE POTENTIAL BEING THERE...WILL ISSUE WINTER STORM WATCH FOR SOUTHEAST MOUNTAINS AND PLAINS FOR TNGT. HATE TO SINK MY TEETH INTO A 2ND PERIOD ADVISORY OR WARNING BASED ON ONLY ONE MODEL RUN. HOPEFULLY 12Z/15 WED MODEL RUNS WILL HAVE GOOD CONTINUITY WITH THIS RUN. THIS WILL GIVE THE DAYSHIFT ONE MORE MODEL RUN TO PROVIDE A MORE DETAILED WEATHER PICTURE. FOR SOUTHWEST/CENTRAL MOUNTAINS AND SAN LUIS VALLEY...DYNAMICAL FORCING SHOULD GENERATE AT LEAST SCATTERED SNOW SHOWERS. COULD RULE OUT SOME SIGNIFICANT SNOW BLOWING THROUGH LA VETA PASS TOWARDS FORT GARLAND. THU: DEPENDING ON WHICH MODEL YOU BELIEVE...THE STORM SYSTEM SHOULD BE PULLING AWAY FROM SOUTHEASTERN CO PLAINS EARLY THU MORNING. STILL A DEFORMATION ZONE CLOUD AND PRECIPITATION SHIELD THREAT FOR 77/81 EARLY THU MORNING...BUT OVERALL TREND WILL BE IMPROVING WEATHER CONDITIONS. MAX TEMPS WILL BE TRICKY DEPENDING ON HOW MUCH SNOW FALLS. PLAN TO GO JUST BELOW MOS TEMP GUIDANCE. EXTENDED(FRI-SUN): VERY QUICK LOOK AT NEW MRF REVEALS INTERESTING AND CHALLENGING PATTERN. POOR RUN-TO-RUN CONTINUITY. NOW...NEXT POTENTIAL WEATHER SYSTEM DOESN'T MAKE IT INTO CO AND CUTS OFF IN THE GREAT BASIN AND WONDERS INTO THE DESERT SOUTHWEST. STILL TRENDING WITH AN ACTIVE WEATHER PATTERN...THOUGH. NO CHANGES TO EFP. MUCH COORD WITH DEN/ABQ/GLD/DDC...THANKS A BUNCH! .PUB...WINTER STORM WATCH 67/71/72 FOR MID AFTERNOON THROUGH TONIGHT WINTER STORM WATCH 65/66/68/70/73>81 TONIGHT METZE BRTP co AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE DES MOINES IA 1010 AM CST WED MAR 15 2000 SHORT TERM... SURFACE TROUGH HAS PASSED THROUGH MIW-DSM-AIO LINE, WITH COLD FRONT NOT FAR BEHIND. DECENT PRESSURE RISES NOW IN NW IA WHICH SHOULD ALLOW FRONT TO CATCH UP WITH THE TROUGH SOON. CLEARING IS FAST APPROACHING THE NW CWA SO HAVE MENTION DECREASING CLOUDINESS IN THE NW. DENSE FOG IS LIFTING IN THE SE, ALLOWING FOR SOME SUN TO BREAK THROUGH, BUT ST DECK IS FAST APPROACHING RIGHT BEHIND TROUGH PASSAGE. ANOTHER ST DECK HAS FORMED BEHIND THE COLD FRONT AS WELL. CLOUDS WILL LIMIT SURFACE HEATING QUITE A BIT IN SE IA, BUT TOP AND OAX SOUNDINGS ARE SUPPORTIVE OF ELEVATED CONVECTION WHERE BEST 1000-850MB CONVERGENCE IS OCCURRING NEAR AND JUST BEHIND TROUGH. DECENT SHEAR AS WELL ALONG WITH LOW FZG LEVELS. PEA HAIL COVERED THE GROUND EARLIER THIS MORNING IN BOONE COUNTY, AND WOULDN'T BE SURPRISED TO SEE SMALL HAIL AGAIN LATER TODAY. RUC FORECAST SHOWS BEST 1000-850MB MOISTURE CONVERGENCE OVER SE IA INTO NORTHERN AND WEST CENTRAL MO BY 21Z. SHORTWAVE OVER SW KS IS SHEARING OUT, BUT THE ETA HAS CONTINUED WEAK TO MODERATE ISENTROPIC LIFT ALONG THE 295K SURFACE ABOVE THE LOW LEVEL COLD AIR THIS AFTERNOON. THIS SHOULD BE SUFFICIENT TO KEEP A COUPLE BANDS OF -SHRA IN CENTRAL ZONES BEHIND COLD FRONT. .DSM...NONE KULA ia AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND 856 AM MST WED MAR 15 2000 UPDATED ZONES TO INCLUDE WIND ADVISORY. FIRST FRONT HAS MOVED SOUTH OF THE AREA WITH HIGH PRESSURE AND ARCTIC AIR WELL TO THE NORTH. LATEST ETA SURFACE WINDS WHICH USUALLY RUN LOW INDICATE 25 TO 30 KNOTS LATER TODAY. RUCII ALSO INDICATING 25 TO 30 KNOTS AROUND 21Z WHICH WILL BE AROUND MAX HEATING. REMAINDER OF FORECAST LOOKS GOOD. .GLD...WIND ADVISORY IN EFFECT UNTIL 5 PM MST (6 PM CST) FOR ALL OF NORTHWEST KANSAS AND EXTREME SOUTHWEST NEBRASKA THEDE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 850 PM CST WED MAR 15 2000 02Z SFC ANALYSIS SHOWING AN AREA OF LOW PRESSURE IN EXTREME SOUTHEAST TEXAS NEAR KBPT OF JUST OFF SHORE THIS EVENING. THIS LOW IN COMBINATION WITH WEAK SFC THETA-E GRADIENT AND SHARP INSTABILITY AXIS HELPING TO TRIGGER A NARROW LINE OF LOW-TOPPED THUNDERSTORMS ACROSS THE LAKES AREA OF EASTERN TEXAS INTO NORTHWEST LOUISIANA. MOISTURE CONVERGENCE BEING AIDED BY THIS WEAK INSTABILITY AXIS EVIDENT ON LATEST LAMP DATA. WATER VAPOR IMAGERY CONTINUES TO INDICATE DRIER AIR FILTERING IN ACROSS CENTRAL LOUISIANA MAKING ITS WAY NORTHEAST BUT AM SOMEWHAT CONCERNED WITH LATEST RUC MODEL WHICH DESTABILIZES THE ATMOSPHERE TO OUR SOUTH AND EAST AS THE DRIER MID LEVEL AIR LIFTS NORTHEASTWARD. MAY NEED TO BUMP NORTHWEST LOUISIANA POP UPWARDS A TAD TONIGHT CLOSER TO NORTHEAST LOUISIANA VALUES. TEMPS ALSO A CONCERN OVERNIGHT AS THE LATEST RUC 2-METER TEMPS SUGGEST NOT MUCH MOVEMENT FROM WHERE TEMPS ARE CURRENTLY. MAY BUMP TEMPS UPWARD A FEW DEGREES TONIGHT AND MENTION THE POSSIBILITY OF SOME PATCHY FOG IN RAIN AREAS. CONVECTION SLOWLY STARTING TO DECREASE ACROSS N OK/SW KS AS EVIDENT BY WARMING CLOUD TOPS ON IR IMAGERY THIS EVENING. FRONT TO OUR NORTH CONTINUES TO MAKE STEADY PROGRESS BUT SFC LOW ALREADY STARTING TO FORM BETWEEN KLBB AND KCDS SHOULD SLOW FRONTAL MOVEMENT SOME TONIGHT INTO TOMORROW. WILL KEEP LOW POP IN TONIGHT ACROSS EXTREME NORTHWEST BUT BELIEVE PRECIP WILL DIE BEFORE MAKING IT THAT FAR SOUTH AND EAST. 13 .SHV...NONE. la FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 700 AM CST WED MAR 15 2000 MAIN RISE/FALL PRESSURE COUPLET AND STRONGEST CAA DEPICTED BY MSAS NOW SOUTH/SOUTHEAST OF FA. AS A RESULT WINDS NOT COMING UP AS EXPECTED. RUC ALSO RELAXES SFC GRADIENT AND SFC WIND SPEED THROUGH MID MORNING. RETURNS FROM KMVX-88D ALSO DIMINISHING SIGNIFICANTLY WITH AREA VSBYS IMPROVING. SO WHILE BLSN/DRSN EXPECTED IN OPEN COUNTRY DO NOT BELIEVE VSBY WILL SERIOUSLY HAMPER TRAVEL IN SNOW BAND. AS A RESULT WILL CANCELL CURRENT ADVISORY OVR SOUTHERN FA. .FGF...NONE. VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 925 AM EST WED MAR 15 2000 WESTERN GULF COAST SYSTEM SHOULD CONTINUE TO SPREAD MID-HI CLOUDS OUR WAY THIS AFTERNOON. HOWEVER...PCPN WITH THIS SYSTEM SHOULD STAY MAINLY WELL TO OUR SW... AS 12Z RUC MODEL CONFIRMS. SOME BREAKS OF SUNSHINE AT TIMES EVEN IN SE TN/SW NC...BUT SKY CONDITION FORECAST LOOKS BASICALLY ON TRACK. 12Z BNA SOUNDING EASILY SUPPORTS MAX TEMPS OF UPR 60S/NEAR 70...IN LINE WITH ONGOING HIGH TEMPS. NO APPARENT REASON TO UPDATE ZONES AT THIS TIME. .MRX... NC...NONE. TN...NONE. VA...NONE. TG tn TEXAS/OKLAHOMA PANHANDLES FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE AMARILLO TX 925 PM CST WED MAR 15 2000 ...CORRECTED HIGHLIGHTS... UPPER LOW VCNTY CO/UT BORDER CONTINUES TO DIG SE THIS EVE AND IS EXPECTED TO EMERGE INTO W TX S PLAINS LATE TOMORROW AFTN. AHEAD OF THIS...PLENTY OF UPSLOPE PRECIP ALREADY BEING GENERATED ACROSS ERN CO AND BEGINNING TO SPREAD S INTO NRN NM. SOME ECHOS SHOWING UP ON AMA 88D ACROSS TEXAS COUNTY OK ATTM. 00Z ETA/NGM/RUC CONTINUE TO SUPPORT EARLIER THINKING THAT HEAVIEST PRECIP WILL BE ACROSS NRN ZNS. AREAS OF H7 WAA/STRONG ISENTROPIC LIFT ON 300K SFC AND UPPER LEVEL DIVERGENCE WILL DEVELOP/ENHANCE PRECIP IN NW ZNS LATE THIS EVE THEN SPREAD E ACROSS OK PNHDL OVERNIGHT. INITIALLY THICKNESS VALUES WILL BE WARM ENOUGH TO BEGIN AS RAIN THEN COLDER AIR WILL SPREAD S ALONG NM BORDER FOR CHANGE TO SNOW. MAIN CONCERN OVERNIGHT IS CHANGE TO SNOW IN NE ZNS AND ACCUMULATIONS THERE BEFORE DAWN. FEEL THAT SNOW WILL NOT BEGIN ACROSS ALL OF NE UNTIL CLOSER TO SUNRISE...HOWEVER SIGNIFICANT UVM COULD SWITCH SOONER. CONVECTION ALSO NOT OUT OF THE QUESTION WITH A FEW LIGHTNING STRIKES NOTED IN SW CO LAST HOUR THOUGH THIS SHOULD BE CONFINED MAINLY NR UPPER LOW CENTER. WILL KEEP HEAVY SNOW WARNING GOING AS IS BUT WORD ACCORDINGLY TO DELAY ACCUMULATION IN NE UNTIL LATE TONIGHT. CENTRAL TX PNHDL REMAINS IN FAVORED H7 WAA THROUGH 12Z THU BEFORE IT SHIFTS OFF TO E. ALSO TRACK OF UPPER SYSTEM FAVORS CENTRAL ZNS FOR BAND OF HEAVIER PRECIP SO SNOW ADVSY LOOK GOOD HERE EVEN WITH LATE CHANGEOVER TO SNOW. FEEL FAR SW ZNS WILL BE ON LOWER END THOUGH AS DYNAMICS SHIFT AWAY FM THAT AREA FIRST. OF COURSE SE CORNER WILL BE LAST TO SWITCH OVER AND MAY STRUGGLE TO REACH ADVSY LEVELS. UPDATED ZNS COMING ALONG WITH UPDATED WSW TO TWEAK MAINLY PRECIP ONSET/TYPE FIRST PERIOD. .AMA... TX...HEAVY SNOW WARNING AFTER MIDNIGHT THROUGH THURSDAY TXZ001>006. SNOW ADVISORY AFTER MIDNIGHT THROUGH THURSDAY TXZ007-008-011>013-016>018. SNOW ADVISORY THURSDAY TXZ009-010-014-015-019-020. OK...HEAVY SNOW WARNING AFTER MIDNIGHT THROUGH THURSDAY OKZ001>003. COBB tx TEXAS/OKLAHOMA PANHANDLES FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 925 PM CST WED MAR 15 2000 UPPER LOW VCNTY CO/UT BORDER CONTINUES TO DIG SE THIS EVE AND IS EXPECTED TO EMERGE INTO W TX S PLAINS LATE TOMORROW AFTN. AHEAD OF THIS...PLENTY OF UPSLOPE PRECIP ALREADY BEING GENERATED ACROSS ERN CO AND BEGINNING TO SPREAD S INTO NRN NM. SOME ECHOS SHOWING UP ON AMA 88D ACROSS TEXAS COUNTY OK ATTM. 00Z ETA/NGM/RUC CONTINUE TO SUPPORT EARLIER THINKING THAT HEAVIEST PRECIP WILL BE ACROSS NRN ZNS. AREAS OF H7 WAA/STRONG ISENTROPIC LIFT ON 300K SFC AND UPPER LEVEL DIVERGENCE WILL DEVELOP/ENHANCE PRECIP IN NW ZNS LATE THIS EVE THEN SPREAD E ACROSS OK PNHDL OVERNIGHT. INITIALLY THICKNESS VALUES WILL BE WARM ENOUGH TO BEGIN AS RAIN THEN COLDER AIR WILL SPREAD S ALONG NM BORDER FOR CHANGE TO SNOW. MAIN CONCERN OVERNIGHT IS CHANGE TO SNOW IN NE ZNS AND ACCUMULATIONS THERE BEFORE DAWN. FEEL THAT SNOW WILL NOT BEGIN ACROSS ALL OF NE UNTIL CLOSER TO SUNRISE...HOWEVER SIGNIFICANT UVM COULD SWITCH SOONER. CONVECTION ALSO NOT OUT OF THE QUESTION WITH A FEW LIGHTNING STRIKES NOTED IN SW CO LAST HOUR THOUGH THIS SHOULD BE CONFINED MAINLY NR UPPER LOW CENTER. WILL KEEP HEAVY SNOW WARNING GOING AS IS BUT WORD ACCORDINGLY TO DELAY ACCUMULATION IN NE UNTIL LATE TONIGHT. CENTRAL TX PNHDL REMAINS IN FAVORED H7 WAA THROUGH 12Z THU BEFORE IT SHIFTS OFF TO E. ALSO TRACK OF UPPER SYSTEM FAVORS CENTRAL ZNS FOR BAND OF HEAVIER PRECIP SO SNOW ADVSY LOOK GOOD HERE EVEN WITH LATE CHANGEOVER TO SNOW. FEEL FAR SW ZNS WILL BE ON LOWER END THOUGH AS DYNAMICS SHIFT AWAY FM THAT AREA FIRST. OF COURSE SE CORNER WILL BE LAST TO SWITCH OVER AND MAY STRUGGLE TO REACH ADVSY LEVELS. UPDATED ZNS COMING ALONG WITH UPDATED WSW TO TWEAK MAINLY PRECIP ONSET/TYPE FIRST PERIOD. .AMA... TX...HEAVY SNOW WARNING AFTER MIDNIGHT THROUGH THURSDAY ZONES 001>006. SNOW ADVISORY AFTER MIDNIGHT THROUGH THURSDAY ZONES 007>020. OK...HEAVY SNOW WARNING AFTER MIDNIGHT THROUGH THURSDAY ZONES 001>003. COBB tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 245 AM CST THU MAR 16 2000 LATEST SFC AND MSAS ANALYSIS INDICATING PRESSURE RISES APLENTY ACRS THE UPPER MS RVR VALLEY AS A LARGE CANADIAN HIGH BUILDS SOUTHEAST OUT OF THE NORTHERN PLAINS AND TOWARD IA. INFLUX OF MUCH COOLER AND DRIER AIR IS UNDERWAY ON NOSE OF BRISK LOW-LEVEL NORTHERLY FLOW. LATEST REGIONAL 88D LOOPS INDICATING POST-FRONTAL COLD RAIN ACRS NORTHEAST MO...INTO NORTHEAST IL...WITH FAR SOUTHERN CWA GETTING CLIPPED BY THIS ACTIVITY. MAIN CONCERNS/QUESTIONS THIS FCST ARE LINGERING PRECIP ACRS THE SOUTH... CLOUD COVER AND TEMPS. SHORT RANGE MODELS REASONABLY SIMILAR/ALTHOUGH NGM AND AVN CONTINUE TO BE MORE AMPLIFIED THAN ETA WITH HEIGHT FIELDS/ WITH ACTIVE/PROGRESSIVE LONG WAVE TRANSITION TO THE EASTERN GRT LKS BY FRI MORNING AS UPPER RIDGING BUILDS ACRS THE UPPER MIDWEST. LOOKING AT PRECIP FIELDS...ETA TOO FAR NORTH AT 06Z WITH POST-FRONTAL PRECIP RIBBON ACRS NORTHERN MO... INTO CENTRAL AND NORTHEAST IL. NGM BEST WITH PRECIP HANDLING...BUT STILL A BIT TOO FAR NORTH. ALL MODELS LINGER PRECIP ACRS THE FAR SOUTHERN CWA AFTER 12Z THIS MORNING...BUT IT DOES GET SHUNTED SOUTH BY 18Z AS SOUTHWARD PROPAGATING SFC RIDGING HAS IT/S AFFECT. CRASHING H85 TEMPS AND CRITICAL THICKNESSES SUPPORT MIX OR CHANGE OVER TO SNOW THIS MORNING BEFORE IT MOVES OUT OF THE CWA. IF IT LINGERS TOO LONG AFTER SWITCH OVER...COULD BE SOME SLUSHY ACCUMULATION. WILL CONTINUE TO WATCH 88D/SATELLITE LOOPS FOR PRECIP TRENDS TOWARD ISSUANCE TIME TO ADJUST ZONE WORDING/GROUPING FOR LINGERING PRECIP THIS MORNING. SFC RIDGING TO CONTINUE TO BUILD ACRS THE UPPER MS RVR VALLEY THROUGH TONIGHT...ALTHOUGH WITH COMBINATION OF LINGERING CYCLONIC FLOW ALOFT... ANOTHER VORT SHEARING ACRS UPPER MIDWEST THIS AFTERNOON...AND GLANCING BLOW OF H5 -24 TO -28 C COLD POOL COULD LEAD TO CU DEVELOPMENT. MID LEVEL AND 1000-H5 LAPSE RATES MARGINAL AT BEST THOUGH THIS AFTERNOON. BEST H85-H5 CONVERGENT QG FORCING ASSOCIATED WITH VORT GLANCE THE NORTHEAST CWA AND MAINLY WI THIS AFTERNOON. ETA EVEN HINTS AT INSTABILITY SHOWERS ACRS FAR NORTHERN IL AND SOUTHERN WI THIS AFTERNOON. WITH THIS CU POTENTIAL AND LATEST IR LOOP SHOWING MID TO HIGH LEVEL CLOUDINESS STREAMING NORTHEAST OVER EAST IA ALONG RUC H7-H3 MB THICKNESS PATTERN OFF SOUTHEAST PLAINS CONVECTION...WILL CONTINUE ONGOING PARTLY CLOUDY WORDING FOR TODAY...ALTHOUGH FEEL FAR NORTHWEST CWA MAY BE MOSTLY SUNNY FOR MOST OF AFTERNOON. TIME SECTIONS ALSO SHOW VEERING LOW LEVEL DRIER/COOLER FLOW TO NORTH-NORTHEAST WILL SCOUR OUT LOW LEVEL RH/S... WHILE HIGHER MID TO HIGH LEVEL RH/S LINGER INTO MID AFTERNOON BEFORE DEEPER LAYER DRYING COMMENCES ACRS THE CWA LEADING TO CLEAR AND CHILLY NIGHT. LOW LEVEL CLOUDS WILL BE LAST LEAVE FAR SOUTHERN CWA...MAYBE NOT UNTIL LATER THIS AFTERNOON. SFC AND UPPER RIDGING TO THEN CONTINUE CLEAR AND DRY CONDITIONS THROUGH FRI NIGHT. LOOKING AT TEMPERATURES...H85 TEMPS LOOK TO COOL TO -4 TO -9 C BY 00Z FRI. WITH SOME MARCH INSOLATION AND LOW LEVEL THERMAL PARAMETERS AND SOME MIXING...FEEL WARMER FWC FOR HIGHS TODAY THE WAY TO GO. FAN/FWC CLOSE TONIGHT ON LOWS...BUT WITH NO SNOW COVER AND STILL SOME WIND... FEEL MID TEENS BIT TOO COOL AND MAY ADJUST A CATEGORY UP. SUNSHINE AND SOME RETURN FLOW TO EAST-SOUTHEAST ON FRI SUPPORT WARMER NUMBERS AS WELL...ALTHOUGH SFC TRAJECTORIES BRING AIR FROM SOUTH RIDGE CENTER SOURCE REGION OVER GRT LKS. H85 TEMPS TO RECOVER TO AROUND -4 TO -6 C SUPPORTING SOME MID 40S BY LATE FRI AFTERNOON. .DVN... IA...NONE. IL...NONE. MO...NONE. JDH il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 900 PM EST WED MAR 15 2000 SYNOPSIS: AN AREA OF LOW PRESSURE WILL MOVE NORTHEAST ACROSS QUEBEC BRINGING SOME LIGHT SNOW...SLEET AND RAIN MAINLY TO NORTHERN MAINE OVERNIGHT. AS THIS LOW MOVES AWAY...IT WILL BRING ANOTHER COLD FRONT ACROSS NORTHERN AREAS THURSDAY MORNING WHICH WILL REACH THE COAST THURSDAY EVENING. A MORE SIGNIFICANT STORM SYSTEM WILL MOVE OUT OF THE TENNESSEE VALLEY TOWARD NEW ENGLAND THURSDAY NIGHT INTO FRIDAY. THIS STORM SYSTEM MAY BRING SOME SIGNIFICANT SNOWFALL AMOUNTS TO DOWNEAST AND THE COAST BY FRIDAY MORNING. TECHNICAL DISCUSSION: LATEST SURFACE ANALYSIS INDICATING COLD FRONT STRETCHING FROM THE MARITIMES ALONG A LINE FROM NEAR KHUL TO CYUL THEN BACK TO LOW PRESSURE OVER NORTHERN LAKE HURON. RUC/18Z MESOETA INTENSIFY LOW PRESSURE AS IT MOVES NORTHEAST ACROSS SOUTHERN QUEBEC PROVINCE. BEST QPF RIDES ACROSS FAR NORTHERN MAINE NORTHWARD INTO CANADA WHERE BEST LYR QG FORCING/OMEGA OCCURS NORTH OF RETURNING WARM FRONT OVERNIGHT. PREVIOUS FORECAST MENTIONING MIXED PRECIP ACROSS THIS AREA LOOKS GOOD TO CONTINUE FOR THE OVERNIGHT HOURS. HOWEVER... SNOWFALL ACCUMULATIONS MAY BE A LITTLE HIGH. WILL LIKELY LOWER TO AN INCH OR LESS BUT LOOK AT LAST MINUTE OBS/RDR BEFORE ZONE ISSUANCE. ELSEWHERE ACROSS CENTRAL AND DOWNEAST MAINE WILL HOLD ON TO PREVIOUS FORECAST AS UPSTREAM RDR COMPOSITE INDICATING PCPN BACK INTO CENTRAL NYS. NOT EXPECTING TO MAKE MANY ADJUSTMENTS TO MIN TEMP FORECAST AS ITS IN GOOD SHAPE. COASTAL WATERS...WITH GRAD TIGHTENING EXPECT WINDS TO REACH MINIMAL GALE LATE TONIGHT/EARLY THU AHEAD OF FRONT APPROACHING FROM THE NORTHWEST. EXPECT GRADIENT TO WEAKEN WITH FRONT IN VICINITY OF COAST LATE THU/THU EVE THEN INCREASE AGAIN TO STRONG GALES WITH LOW PRESSURE INTENSIFYING ALONG FRONT FRIDAY. .CAR...WINTER STORM WATCH ZNS 15>17/29/30 LATE THU NIGHT INTO FRI. GLW. FITZSIMMONS me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1024 PM EST WED MAR 15 2000 RADAR AND SATELLITE TRENDS CONFIRM A DECREASING TREND IN PRECIPITATION AND CLOUD COVERAGE ACROSS NORTHERN MICHIGAN THIS EVENING UNDER THE INFLUENCE OF INCREASE SUBSIDENCE IN LRQ OF UPPER SPEED MAX CUTTING ACROSS NORTHERN LOWER PER 00Z UPPER AIR PLOTS. KAPX 88D SHOWS ONLY PRECIPITATION LEFT JUST CLIPPING GLADWIN/ARENAC/IOSCO COUNTIES...LIKELY IN THE FORM OF SNOW BY NOW ALTHOUGH NO SURFACE OBS IN THAT AREA TO CONFIRM THAT. NO MATTER HOWEVER...AS LINGERING PRECIPITATION SHOULD END BY MIDNIGHT. KMQT 88D HAD BEEN SHOWING SOME NORTH-SOUTH ORIENTED BANDS OF FLURRIES OVER CENTRAL UPPER...BUT RECENT TREND HERE HAS ALSO BEEN ONE OF WEAKENING. MID LEVEL MOISTURE CONTINUES TO PULL EAST... WITH CLEARING NOW OVER FAR EASTERN UPPER AND ACROSS PORTIONS OF FAR NORTHERN LOWER. WITH CLEARING TREND EXPECTED TO CONTINUE OVERNIGHT... MAIN PROBLEM DEALS WITH POTENTIAL FOR LAKE INDUCED CLOUDS AND PRECIPITATION. STRONG CAA IN WAKE OF COLD FRONT WHICH PASSED ACROSS NORTHERN LOWER MICHIGAN DURING THE EVENING HOURS...WITH 925MB TEMPERATURES PLUMMETING TOWARD -16C BY MORNING. 18Z MESOETA/00Z RUC IMPLY INVERSION HEIGHTS ACROSS EASTERN UPPER CLIMBING TOWARD 5K FEET OVERNIGHT...HOWEVER INCREASE IN INSTABILITY OFFSET BY DRIER LOW LEVEL AIR POISED NORTH OF LAKE SUPERIOR AS EVIDENCED BY YPL SOUNDING AT BELOW ZERO SURFACE DEW POINTS. LONG FETCH ACROSS LAKE SUPERIOR SHOULD BE ENOUGH TO KICK OFF SOME CLOUD DEVELOPMENT AND EVEN A FEW FLURRIES. HAVE SEPARATED CHIPPEWA AND MACKINAC COUNTIES TO ACCOUNT FOR DIFFERENCES IN CLOUD COVER. OVER NORTHERN LOWER...INVERSION HEIGHTS NOT IMPRESSIVE BUT PRECONDITIONING OF PARCELS FROM LAKE SUPERIOR INTO NORTHERN LAKE MICHIGAN WILL AID CLOUD DEVELOPMENT. TREND IN LOW CLOUDS IN FOG LOOPS SEEM TO SUPPORT THIS AS WELL. WILL KEEP TVC-CAD AREAS WESTWARD MOSTLY CLOUDY OVERNIGHT...AND MENTION A FEW FLURRIES TOWARD MORNING FOR LAKE MICHIGAN COUNTIES. SIMILAR PROBLEM FOR NORTH FLOW LAKE HURON COUNTIES...THOUGH FETCH IS SHORTER DEW POINTS NOT AS LOW (YET) TO THE EAST OF LAKE SUPERIOR. SO SUSPECT THAT SOME CLOUDS MAY ALSO WORK THEIR WAY INTO SOME OF THE LAKE HURON COUNTIES...ESPECIALLY IF LOW LEVEL FLOW VEERS MORE NORTHEAST TOWARD MORNING AS PROGGED. GOING TEMPERATURES LOOK PRETTY GOOD...WINDS STILL A BIT GUSTY OVER NORTHEAST LOWER IN TIGHTER ISALLOBARIC GRADIENT RIGHT BEHIND FRONT. SURFACE PRESSURE GRADIENT LOOSENS UP A BIT OVERNIGHT...BUT MAY CONTINUE TO SEE SOME GUSTINESS ALONG THE LAKESHORE AREAS. UPDATED ARBZFPAPX WILL BE OUT BY 0330Z. .APX...NONE. JPB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 815 PM CST WED MAR 15 2000 CLOUDS HAVE CLEARED OUT OF AREA AND FORECAST IN PRETTY GOOD SHAPE. TAKING A LOOK AT 00Z RUC SURFACE TEMP FORECAST OVERNIGHT...NEAR ZERO LOOKS GOOD IN FAR NORTH AREA. AT LEAST AS LOW AS TEENS LOOK GOOD IN THE SOUTH. WILL LOWER A BIT FOR SOUTH CENTRAL WITH COLD ADEVCTION STILL GOING ALONG WITH LOW DEW POINTS. .MSP...NONE. JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1040 AM CST WED MAR 15 2000 FORECAST CONCERNS INVOLVE AFTERNOON TEMPERATURES AND SKY CONDITIONS... SATELLITE IMAGERY HAS SHOWN A RAPID CLEARING ACROSS THE NORTHERN CWA LAST FEW HOURS. THIS IS ASSOCIATED WITH STRONG LOW LEVEL COLD ADVECTION/SUBSIDENCE. 12Z RUC SOUNDINGS ACROSS CWA VIEWED IN BUFKIT INDICATED RAPID DRYING FOR THE REST OF TODAY. HAVE GONE WITH MOSTLY SUNNY FAR NORTH...AND CLEARING ELSEWHERE DURING THE AFTERNOON. WINDS SHOULD REMAIN UP AS ADIABATIC LAPSE RATE IS CONDUCIVE TO STRONG DOWNWARD MOMENTUM TRANSPORT. STRONG COLD ADVECTION SHOULD BE OFFSET BY STRONG MARCH INSOLATION. AFTERNOON TEMPERATURES SHOULD BE NEARLY STEADY FROM LATE MORNING READINGS. OF COURSE...NEAR THE IOWA BORDER THE TEMPERATURE WILL DROP A FEW DEGREES MORE AS THE CLOUD COVER LINGERS THERE FOR A TIME. 12Z ETA SHOWS CWA ON CYCLONIC SIDE OF UPPER JET MAX ON THURSDAY. LEFT IN MENTION OF SNOW FLURRIES...ALTHOUGH RELATIVE HUMIDITY PROGS DON'T SHOW MUCH IN THE WAY OF MOISTURE. .MSP...NONE. RJN mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 230 AM EST THU MAR 16 2000 CURRENTLY: WATER VAPOR IMAGERY SHOWED SHORTWAVE TROUGH AXIS LIFTING NEWD ACROSS WRN GULF OF MEXICO. FURTHER DOWNSTREAM...BAND OF WEAKENING CONVECTION MOVING NNEWD FROM NRN GULF INTO MUCH OF THE FL PANHANDLE AND SOUTH ALABAMA. MOST OF THE TSTMS REMAIN OFFSHORE IN REGION OF BETTER LIFT/INSTABILITY PER RUC AND LIGHTNING DATA. MOSTL COPIOUS AMOUNTS OF GULF MOISTURE IN THE FORM OF CONSIDERABLE MID/HGH CLOUDS TRANSPORTED ACROSS THE ENTIRE CWFA. TEMPS VARY LITTLE ACROSS THE CWFA W/ 60S AND DEWPTS IN THE MID 50S-LWR 60S. WINDS WERE GENERALLY LIGHT EAST TO SOUTHEAST OVER INLAND AREAS...AND 10-15 KT NEAR SHORE WATERS TO 15-20 KT WELL OFFSHORE WATERS. SHORT RANGE/ZFP: AMPLIFIED PATTERN TO PERSIST THIS FORECAST CYCLE AS A SERIES OF SHORTWAVES DROP SEWD FROM NRN/CNTRL ROCKIES INTO SRN PLAINS THEN PROGRESS EWD ALONG THE GULF COAST STATES. THE ETA AND AVN HAVE BEEN THE PREFERRED SOLUTIONS W/ THE SOUTHERN STREAM SHORTWAVE TRACKING ENEWD FROM THE WRN GULF OF MEXICO INTO THE SERN U.S. BOTH INITIALIZED BETTER AND WERE MORE AMPLIFIED THAN WEAKER NGM. ETA/AVN TIME-HEIGHT PROFILES DEPICTED MEAN 1000-500 MB RHS AOA 80 PCT FROM 06Z TODAY THRU 06Z FRI...THEN SIG DRYING ABOVE 700 MB THEREAFTER. ALSO STRONG UVV/S ON ORDER OF 4 TO 7 MICROBAR/SEC CENTERED AROUND 18Z TODAY...THEN LIFT ABRUPTLY ENDS AFT 00Z FRI. NOTE: THE AVN IS ABOUT 6 HRS QUICKER W/ MID LEVEL DRYING THAN ETA. BOTH MAINTAIN AMPLE MOISTURE SFC TO 850 MB THRU 48 HRS. AT THE SURFACE...LOW PRESSURE DEVELOPS OVER MS AND TRACKS NEWD TOWARDS THE MID ATLANTIC STATES W/ TRAILING COLD FRONT SWINGING SEWD THRU NWRN PORTIONS OF THE CWFA BTWN 12Z AND 18Z FRI...AND SERN PORTIONS AFT 00Z SAT. FRONT SHOULD LOSE ITS SEWD MOMENTUM AND STALL OVER NRN FL PEN AS NEXT SHORTWAVE/SFC WAVE FORMS OVER TX SAT. SFC WIND PROGS SHOW VEERING FROM SOUTHEAST TODAY TO SOUTHWEST TONIGHT...THEN WEST TO NORTHWEST FRI FOLLOWING FROPA. ETA FORECAST SOUNDINGS SHOW PWAT VALUES INCREASING TO 1.42 INCH WITH LI OF -3 BTWN 12Z AND 18Z TODAY. PWAT VALUES DO DECREASE TO 0.90 INCH FRI AFTN...HOWEVER DECENT INSTABILITY/LOW LEVEL MOISTURE IN PLACE FOR SOME SCT CONVECTION INVOF FRONT. ETA/AVN QPFS QUITE SIMILAR...BUT ETA A LITTLE WETTER AND FURTHER EAST WHEREAS AVN CENTERS BULK OF HEAVIEST RAFL OVER SERN AL/WRN 2/3 FL PNHDL W/ BASIN AVERAGES OF 0.75 TO 1.50 INCH. OVER SW GA/FL BIG BEND 0.50 TO 1.00 INCH BAIN AVERAGES LOOK REASONABLE. ETA FOUS 48 HR TALLIES ABOUT 2/3 INCH FOR TLH WHILE NGM PAINTS A MEAGER 0.01 INCH. FWC/FAN POPS IN CLOSE AGREEMENT FIRST PERIOD...THEREAFTER FAN ABOUT A CAT HIGHER THAN FWC. BASED ON RADAR TRENDS WILL RAISE CURRENT LIKELY TO CATEGORICAL AREAS ALONG/WEST OF ABY TO AQQ LINE AND LIKELY ELSEWHERE. WILL KEEP GOOD CHC POPS SAME AREAS TONIGHT AND LIKELY REMAINING ZONES. FOR FRI...REDUCED POPS TO SLGT CHC NW AND 30-40 PCT CNTRL/SE. WILL UNDERCUT FWC/FAN MAX TEMPS BY A FEW DEGS ACROSS THE BOARD FOR CLOUDS/PCPN. FWC/FAN MIN TEMPS CLOSE AND ACCEPTED. MEDIUM RANGE/EFP: FRONT WEAKENS AS IT BECOMES QUASI-STATIONARY SOUTH OF OUR COASTAL WATERS. A SERIES OF SHORTWAVES MOVING ACROSS THE NRN GULF KEEPING CONDITIONS SOMEWHAT UNSETTLED MAINLY ALONG COAST AND SRN/ERN PORTIONS OF FL CWFA. TEMPS AVERAGING ABOUT 3-5 DEGS BELOW CLIMO MAXIMA W/ NORMAL MINIMA. MARINE: SOUTHEAST WINDS AROUND 20 KTS AND GUSTY BECOMING SOUTH THIS AFTN MAINTAINING SCA STRENGTH...THEN VEER TO SOUTHWEST TONIGHT WHILE DIMINISHING TO SCEC LEVELS. WINDS BECOME NORTHWEST TO NORTH AFTER FROPA FRIDAY AFTN. SEAS SHOULD SUBSIDE LATER TONIGHT AND ESPECIALLY FRI W/ SHORTER FETCH LENGTHS. WILL HOLD ONTO SCT-NMRS SHWRS/TSTMS THRU TONIGHT...THEN DIMINISHING FROM W TO E FRI AS THE FRONT EASES SOUTHEAST THRU THE MARINE AREA. FIRE WEATHER: NO HIGHLIGHTS. PRELIMINARY NUMBERS... TLH 074/061 076/052 7631 PFN 071/064 073/056 8531 DHN 070/060 072/050 9521 ABY 071/060 072/051 9631 VLD 075/061 076/053 6632 TLH... AL...NONE. GA...NONE. FL...SCA GMZ750-755-770-775 TODAY. MAJ fl FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 1027 AM CST THU MAR 16 2000 FCST UPDATE WILL BE ISSUED TO ADDRESS SLIGHT MAX TEMP CHANGES. RUC UPDATES SHOWING FAIR AMOUNT OF LOWER LVL SFC CONVERGENCE AND 1000-700MB RH ALG A TROF SAGGING SWD THROUGH THE CWFA. VIS SAT IMAGERY SHOWING CLEARING ACROSS THE NRN ZONES WITH THICKER MID LV CIGS ACRS THE SRN AND SWRN ZONES...WELL MODELLED BY RUC. CURRENT FCSTS INDICATE PARTLY SUNNY CONDS ACRS NRN ZONES...AND WITH SOME CU ALREADY EVIDENT IN PEMBINA CNTY...WILL EXPECT SCT-BKN CU FIELD LATER TDY. 12Z ETA INITIALIZED FAIRLY WELL ON VORT CNTR IN SERN MAN...MVG JUST NORTH OF MN/ONT BDR THROUGH TDY. SO SUBSIDENCE CAP WILL INHIBIT TO MUCH BUILD UP. TEMPS DVL-GFK WARMING AHEAD OF MOS HEATING CURVE SO WILL BOOST FCST MAX TEMPS 3-5 DEGREES IN NRN AND NWRN ZONES. .FGF...NONE. GUST nd SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 230 PM CST THU MAR 16 2000 SOUTHERN AND CNTRL LA AND SOUTHEAST TX REMAINS IN THE WARM SLOT AS CU FIELD DEVELOPING ACROSS THIS AREA THIS AFTERNOON. A WEAK SFC TROF IS DEFINING THE BNDRY BETWEEN SHWRS AND TSTMS ACRS SOUTH-CENTRAL AND EASTERN LOUISIANA WITH NLY FLOW AT SFC EXPERIENCED OVER SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA AND SOUTHERLY IN ADV OF THE SFC TROF. SFC LOW OVR CNTRL TX WITH STALLED COLD FRONT DRAPED FROM CENTRAL TX INTO AR WITH PRECIP OVER RUNNING BNDRY INTO THE COLD SECTOR. SHARP DEMARCATION IN FRNTL BNDRY WITH TEMPS RANGING FM 75 TO 80 IN ADVANCE OF THE FRNTL BNDRY AND 38 TO 42 BEHIND THE BNDRY THIS AFTN. COLD FRNT BEGINS TO MOVE SOUTHWARD WITH UPPER LVL SUPPORT. FRONT MOVES INTO THE AREA TMRW. ENOUGH UPPER LEVEL SUPPORT AND LOW LEVEL INSTABILITY WILL BE IN PLACE. THE TRIGGER FOR THIS EVENT WILL BE THE STORMS IN ADVANCE OF THE FRONTAL BNDRY. OVRNGHT STORMS LOOK TO MOVE INTO EXTREME SE TX AND SOUTHERN LA TOWARDS SUNRISE AND THOUGH FORECAST AREA BY THE AFTERNOON HOURS. BELIEVE THAT ENOUGH FEATURES ARE IN PLACE THAT FEW STORMS TMRW MAY BECOME SEVERE ALONG AND JUST IN ADVANCE OF FRONTAL BNDRY. AS FOR MDLS... WELL THEY INITIALIZED WELL... THEN BEGIN TO DIVERGE WITH ETA AND NGM HANGING TOGETHER WHILE AVN AND RUC GO THEIR OWN WAY. BELIEVE THAT UPR LVL CLOSED CUT OFF LOW WILL MOVE SLOWLY INTO EASTERN TX BY TMRW AFTN. AS A RESULT... STRONG FRNTL PUSH NOT IN PLACE AND THEREFORE FRNTL BNDRY BECOMES HUNG-UP OVER THE COASTAL WATERS TMRW AFTN. COLD AIR ADVECTION WILL DEVELOP BEHIND THE FRNT FOR FRIDAY EVE. OVERRUNING BEHIND THE FRONT WILL CONT PRECIP INTO FRIDAY EVE TAPERING OFF BY EARLY SAT MRNG AS UPR LVL LOW KICKS OFF TWRDS THE NE. SKIES GRADUALLY CLEARING THROUGH THE DAY. .LCH... LA...NONE TX...NONE PRELIM NUMBERS... BPT 61/73/52/70 3630 LCH 61/72/48/69 3630 LFT 61/73/52/68 2630 AEX 60/69/43/65 2630 K. KUYPER la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 230 PM CST THU MAR 16 2000 CHANCES OF RAIN WILL BE GOING UP ONCE AGAIN TO OUR WEST OVERNIGHT WITH BETTER CHANCES DURING THE DAY FRIDAY ACROSS NORTH LOUISIANA. 18Z SFC ANALYSIS DEPICTS TWO DIFFERENT AIR MASSES ACROSS THE LOWER MISSISSIPPI VALLEY/SOUTHERN PLAINS STATES THIS AFTERNOON. CONTINENTAL POLAR AIRMASS TO OUR NORTH AND MOISTURE LADEN SUBTROPICAL AIR MASS ACROSS THE FOUR STATE REGION. WEDGED IN BETWEEN THE TWO LIES A SHARP COLD FRONT WHICH ACCORDING TO MY ANALYSIS WAS LOCATED FROM JUST NORTH OF HOT AND PRX TO WEST OF DFW DOWN TO NEAR JCT. SFC LOW PRESSURE WAS LOCATED NEAR KJCT WHICH HAS HELPED TO STALL THE FRONTS SOUTHWARD PROGRESS FOR THE TIME BEING. WEAK PRE-FRONTAL TROUGH...BUT NOT THE ACTUAL FRONT...WAS LOCATED ALONG THE I20 CORRIDOR FROM JUST SOUTH OF TYR...SHV AND MLU. THIS TROUGH HAS HELPED TO SWITCH OUR WINDS AROUND TO THE NORTHWEST BUT AS THE LATEST RUC MODEL INDICATES...PLENTY OF INSTABILITY EXISTS NORTH OF THIS TROUGH ACROSS THE MIDDLE RED RIVER VALLEY OF NORTHEAST TEXAS AND SOUTHWEST ARKANSAS. MODELS SURPRISINGLY SIMILAR WITH THEIR PROGRESSION OF STRONG SHORTWAVE ENERGY ROTATING THROUGH THE SOUTHERN ROCKIES AND INTO EXTREME WEST/ SOUTHWESTERN TEXAS AT THIS TIME. WHERE THE MODELS DIVERGE IS WITH THEIR QPF FORECASTS THROUGH THE NEXT 48 HRS. THE STRANGEST OF ALL IS THE NGM WITH ITS LIKELY POPS ACROSS NORTH LOUISIANA FOR FRIDAY YET NO QPF GENERATED ON 12Z FOUS OUTPUT. ONE THING THAT IS FOR CERTAIN IS THE MODELS CONSISTENCY IN SLOWING THE SHORTWAVE DOWN FROM RUN TO RUN WHICH WOULD TEND TO LEAVE A MAJORITY OF THE PRECIP ACROSS EASTERN TEXAS...SOMETHING ALL MODELS AGREE WITH. FOR THIS REASON...WILL KEEP POPS HIGHEST OVERNIGHT AND FRIDAY ACROSS EASTERN TEXAS AND TAPER POPS LOWER TOWARDS THE EAST. RAIN SHOULD BE ENDING FROM WEST TO EAST LATE FRIDAY AS SHORTWAVE GETS A KICK EASTWARD DUE TO POSITIVELY TILTED SHORTWAVE ENERGY ENTERING THE CENTRAL PLAINS...SOUTHERN GREAT BASIN. THIS SECOND SHORTWAVE COULD HAVE ENOUGH MOISTURE TO WORK WITH TO GENERATE SOME PRECIPITATION BUT BELIEVE THIS WOULD OCCUR LATE ENOUGH ON SATURDAY TO LEAVE DAY PERIOD DRY FOR NOW. MUCH UNCERTAINTY EXISTS LATE INTO THE WEEKEND WITH THE MRF VERY INCONSISTENT THE LAST SEVERAL DAYS. PRELIMS TO FOLLOW...13 SHV 53/59/47/60 3651 MLU 52/61/46/60 2552 TXK 48/56/45/58 4651 TYR 52/57/47/62 7741 LFK 57/63/49/66 6741 .SHV...NONE. la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1015 AM CST THU MAR 16 2000 FORECAST HAS BEEN UPDATED TO REFLECT INCREASE IN CLOUDINESS WRN ZONES...ALTHOUGH LATEST RUC IS DRIER THAN PREVIOUS RUNS OR 06Z ETA...SATELLITE IMAGERY WOULD INDICATE CONSIDERABLE CLOUDINESS INTO W CENTRAL. FORECAST ALSO HAS MINOR TEMPERATURE UPDATES BASED ON CLOUDS AND LATEST RUC MODEL. .MSP...NONE. SCOTT mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 503 AM CST THU MAR 16 2000 SFC ANLYS AT 0900 UTC SHWS CD FNT THRU FCST AREA. 0600 UTC INITIAL RUC CROS-SECT DATA SHWS TOP OF FNTL SLOPE ARND 850 HPA WITH WEAK ISENTROPIC UPGLIDE JUST ON TOP OF FNTL BNDRY WHICH IS HELPING TO KEEP PCPN TOGETHER OVR SE PERIPHERY OF CWA. LATEST RUC KEEPS MENTIONED ISENTROPIC LIFT OVR CNTL MO THRU 1800 UTC. ENVIRONMENT OVR THIS RGN STILL WRM ENOUGH FOR LIQUID PCPN BUT FCST SNDG DATA STILL POINTING TWRDS COOLING OF LYR BY MIDDAY. WENT WITH CATEGORICAL PCPN TDY IN THIS AREA AND WORDED FCST -RA MIXING WITH -SN AT TIMES. FTHR TO NW AREA COVERING 30 MILES EITHER SIDE OF MKC IRK LN SCT LGT PCPN INDICATED BY 88-D. SFC OBS REPORTING -RA ATTM BUT WITH ENVIRONMENT SLIGHTLY COOLER THINK THAT HEAVIER BURSTS OF PCPN THIS AM SHLD FALL AS -SN. KEEPING AND EYE ON DEFORMATION ZN OVR S CNTL KS. MODEL QPF DRAGS RGN OF PCPN ALG AND S OF MO RVR BUT MID TROPOSPHERIC CNVGNC OF Q-VECTORS INDICATES RMNS OF THIS DEFORMATION ZN MAY TRACK FTHR N PSBLY THRU MCI/STJ AND MV INTO MUCH OF N CNTL MO. MODELS APPR TO BE PICKING UP ON WEAK PHASING BET NRN/SRN BRANCHES AS MID/UPR TROPOSPHERIC FRONTOGENETIC FORCING FIELDS INDICATE LIFT OVR SRN TWO THIRDS OF CWA THRU TDY. WITH THIS IN MIND AND THE FACT THAT BOTH NGM/ETA IN NO HURRY TO SWEEP 3-4 G/KG SPEC HUMIDITIES OUT OF CWA KEPT POPS IN FCST ALL DAY THUR. IN XTRM NW MO WHERE DRIER AIR ALREADY NOSING INTO RGN REMOVED POPS FOR TDY BUT KEPT CLDY. DUE TO XPTD SLO ADVANCEMENT OF DEFORMATION ZN WOULD NOT BE SURPRISED TO SEE CLDS HANG IN MOST OF TNGT. CLD CVR SHLD KEEP TEMPS IN NEIGHBORHOOD OF FWC/FAN GUIDANCE TDY/TNGT. THEREFORE STAYED WITH CRNT TEMPS TDY OPENED RANGE UPWARD FOR TNGT'S MINS. DRY WX STILL LKS LIKE THE DEAL FOR ST PATTY'S DAY BUT LWR TROPOSPHERIC MSTR RETURNING WITH SE FLW LATE FRI NITE AND SAT COUPLED WITH FCST PROXIMITY OT RIGHT ENTRANCE RGN OF LIFTING JET DURING THE DAY SAT RE-INSERTED POPS FOR SAT. MADE LTL OR NO CHGS TO REST OF EFP. WILL HIT AM SPS HARD WITH CD TEMPS TNGT SINCE QUITE A BIT OF VEGETATION HAS COME OUT IN RECENT WEEKS DUE TO WRM WX. .EAX...NONE. BODNER mo SOUTHEAST TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 145 PM CST THU MAR 16 2000 COLD FRONT HAS CONTINUED TO RACE SOUTH THROUGH WESTERN TEXAS. WX BEHIND THE FRONT HAS BEEN LIKE STEPPING THROUGH A DOOR INTO WINTER. 11Z ABI 61F/47DWPT 19009KT...18Z 39F/37DWPT 2.5SM-RA 36019G28KT. AT 18Z FRONT ALONG A LINE FROM NEAR ADM-NW OF MWL-SJT...THE EASTERN END OF THE LINE SHOULD MOVE SLOWLY AS UPPER LOW TRACKS EAST ACROSS N TX. EXPECT THE WESTERN END OF THE LINE TO CONTINUE SOUTH. WARM SECTOR OF SFC LOW NE OF JCT AND ALONG AND NORTH OF THE QUASI-STATIONARY FRONT EAST OF LOW SHOULD BECOME THE FOCUS FOR CONVECTION TO DEVELOP AND SPREAD SE. RUC AND GOES SOUNDERS INDICATING LI IN THIS SECTOR -7 TO -10 ATTM. WOULD NOT BE SUPRISED TO SEE A SVR WATCH SHORTLY. MODELS INDICATE THE BEST LIFT TO SWEEP ACROSS SETX TONIGHT AS UPPER VORT LOBE ROTATES AROUND THE LOW. SUFFICIENT MOISTURE WILL HAVE RETURNED TO SETX TONIGHT (PW INCREASE TO 1.1-1.2"). 500MB TEMPS A CHILLY -16 TO -18 ACROSS SETX AT 06Z. EXPECTING A LARGE CONVECTIVE SYSTEM TO DEVELOP WITH HAIL BEING A SERIOUS THREAT. MID LEVELS ARE FAIRLY DRY BUT WINDSPEEDS ARE ONLY RUNNING 10-40 KNOTS PER ETA...AVN HAS A STRONGER MID LEVEL WIND FIELD. WOULD CERTAINLY NOT RULE OUT DAMAGING WINDS TONIGHT. LL WINDS ARE STRONGLY VEERING BUT ARE WEAK - LOWERING THE THREAT OF TORNADOES. FRONT SHOULD REACH THE COAST AROUND 12Z FRIDAY. AS YOU CAN GUESS FROM DISC SO FAR WILL MENTION SVR OVER THE CWA FOR TONIGHT. NEXT ISSUE IS THE SLOW MOVEMENT OF THE UPPER SYSTEM. INSTABILITY REMAINS ACROSS SETX FRIDAY AS 850 WINDS PROGGED TO REMAIN SOUTHERLY THROUGH 18Z THEN BECOMING SW. CLOUD COVER WILL REMAIN OVER THE AREA FRIDAY AS SECOND VORT LOBE IN THE WINGS TO MOVE THROUGH FRIDAY AFTERNOON. THREAT OF RAIN WITH ELEVATED SHRA/TSRA WILL CONTINUE FRIDAY. RAIN SHOULD TAPER OFF BY SATURDAY MORNING. 850 FRONT NEARS THE COAST SATURDAY EVENING BUT CAA WILL DROPPED OFF. MOSTLY CLOUDY CONDITIONS WILL LIKELY LINGER THROUGH SATURDAY. FOR MARINE...WILL LOWER THE WINDS BELOW SCA CRITERIA. LATEST MODELS INDICATING WINDS WILL BE LOWER THAN PREVIOUSLY THOUGHT. .KHGX...NONE 45/40 PRELIMS CLL RE 052/059 046/065 046 773 IAH RE 054/063 050/065 049 663 GLS RE 063/065 057/067 059 554 tx AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE LUBBOCK TX 1125 AM CST THU MAR 16 2000 WILL DROP THE WINTER WEATHER ADVISORY ON THE UPDATE. RADAR AND SATELLITE TRENDS INDICATE BEST LIFT ASSOCIATED WITH LOW LEVEL WARM AIR ADVECTION WAS ADVANCING TO THE NORTHEAST OUT OF THE NORTHEAST QUADRANT OF THE FORECAST AREA LATE THIS MORNING. 15Z RUC/12 ETA SHOWED BEST WARM AIR ADVECTION AT 85H OCCURRING FROM THE ROLLING PLAINS INTO THE EASTERN TEXAS PANHANDLE INTO NORTHWEST OKLAHOMA THIS AFTERNOON. THE SOUTHEAST TEXAS PANHANDLE WILL BE IN THE TRANSITION ZONE BETWEEN RAIN TO SLEET TO SNOW AS THE 85H FREEZING LINE SLOWLY TRANSLATES SOUTHEAST ACROSS THIS AREA DURING THE AFTERNOON. WITH WARM GROUND TEMPERATURES AND SLOW TRANSITION TO WINTRY PRECIPITATION...WILL NOT ISSUE A WINTER WEATHER ADVISORY FOR THIS AREA ATTM. ELSEWHERE...85H-50H LAYER Q-VECTOR CONVERGENCE ZONE MOVES INTO WESTERN OKLAHOMA THIS AFTERNOON ASSOCIATED WITH THE 85H WARM AIR ADVECTION. THE UPPER LEVEL DYNAMIC LIFT ASSOCIATED WITH UPPER LOW SOUTHEAST OF ALBUQUERQUE WILL SHIFT SOUTHEAST INTO THE PERMIAN BASIN AS UPPER LOW CONTINUES TO MOVE SOUTHEAST INTO THIS AREA BY EARLY THIS EVENING. THIS IS SUPPORTED BY THE 12Z ETA WHICH INDICATED 50H-30H LAYER Q-VECTOR CONVERGENCE SHIFTING SOUTHEAST THROUGH THIS AREA. RADAR SEEMS TO SUPPORT THIS AS WELL AS WEAK SHOWERS CONTINUE TO DEVELOP OVER SOUTHEAST NEW MEXICO AND MOVE EAST. THE WIND SPEEDS ARE STARTING TO DIMINISH SLIGHTLY AND WILL MAKE CORRESPONDING CHANGES TO THE FORECAST. TEMPERATURES SHOULD REMAIN STEADY OR SLOWLY RISE A CATEGORY THIS AFTERNOON FROM CURRENT READINGS. WILL REMOVE MENTION OF POPS FOR ALL SOUTH PLAINS ZONES FOR THIS EVENING AND TAPER THEM FOR THE ROLLING PLAINS. FRIONA/TULIA 034/022/054/034 2-0 CHILDRESS 035/026/052/035 +31 BROWNFIELD 039/026/057/038 310 LUBBOCK 036/025/056/036 310 ASPERMONT 038/030/055/040 531 .LBB...NONE. tx