Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 09/01/19
Area Forecast Discussion
National Weather Service Houston/Galveston TX
747 PM CDT Sat Aug 31 2019
.DISCUSSION...
Strong showers and thunderstorms developed today across several
portions of southeast Texas. These thunderstorms lingered during
the evening hours across the northern half of the CWA, where the
highest levels of low level moisture resided. Several Special
Weather Statements and Flood Advisories were issued during the
afternoon hours. At 00Z (7 PM CDT), thunderstorms were observed
over the Austin and San Jacinto counties, while the rest of the
activity had dissipated to light to moderate showers. A slight
chance of isolated showers and thunderstorms will continue over
the northwest quadrant tonight. Elsewhere, little to no rainfall
is expected. Low temperatures tonight will be in the mid to upper
70s.
Sunday, a drier weather pattern is expected as an area of
drier air moves westward into the region and a mid level ridge
amplifies over the Four Corners region. One this forecast update,
the PoPs were increased this evening and early tonight and
temperatures were slightly adjusted to represent the current
surface observations. The rest of the forecast continues on track.
24
&&
.PREV DISCUSSION... /ISSUED 708 PM CDT Sat Aug 31 2019/
AVIATION...
SHRA/TSRA will end with the loss of heating. VFR conditions are
expected to prevail overnight as drier moves into the region.
Moisture levels will slowly fall throughout Sunday. Will keep
the TAFs dry on Sunday with just scattered clouds developing in
the late morning. Winds will remain light through the TAF cycle.
43
PREV DISCUSSION... /ISSUED 358 PM CDT Sat Aug 31 2019/
SHORT TERM [Tonight through Sunday]...
Radar shows scattered showers and storms across the area that are
primarily mesoscale driven by outflow boundaries. Storms are pulse
storms and typically have short life cycles. AMDAR soundings from
airplanes support thunderstorm activity which should be slow
moving if at all since there are very weak wind profiles. Storm
activity should decrease towards sunset as instability is lost and
most storms have gusted out with outflow cutting off inflow.
Overnight we should have fairly quiet conditions and expect low
temperatures to get into the upper 70s inland, maybe mid 70s. Wind
will be calm so there could be some patchy fog but not enough to
really drop visibility much.
Water vapor imagery and derived precipitable water imagery shows
an area dry air over the central Gulf which should move over the
area tomorrow. As a result we kept rain chances on the low side
for most areas, but there could be a brief isolated shower to pop
during the afternoon. There will be a trough axis in the area but
think the drier air will limit activity tomorrow.
Overpeck
LONG TERM [Tuesday Through Saturday]...
With the upper ridge progged to build back into the state (from the
Four Corners), the overall forecast trend(s) for next week are
likely to be warming temperatures/decreasing rain chances. This
feature could be a factor during the start of the week as we
monitor the approach of a weak tropical wave from the southern
Gulf. For the most part, models are moving this system onshore
south of our CWA...into the middle/lower TX coast by Wed. Given
this track, the best/higher rain chances will likely be over the
southern half of the CWA/along the coast. The proximity to the
deeper moisture, along with daytime heating and the seabreeze
should be enough for scattered (mostly di- urnal) activity Mon and
Tues. Further inland, high temperatures are expected range in the
upper 90s to near 100, with no POPs.
The latter part of the upcoming week will depend on what and where
this tropical wave goes...and perhaps (to some extent) Dorian.
Per these current runs...offshore winds developing over the
Mississippi River Valley could push briefly into SE TX around mid
week in the wake of these systems. Then with a weak/broad surface
high forming over the region along with the upper ridge trying to
re-assert itself across the state (from the west), we could be
seeing some very warm temper- atures for most of the CWA during
this time frame. 41
MARINE...
A weak tropical wave (currently situated in the south/southwestern
Gulf of Mexico) will continue moving westward this weekend into the
early part of next week. Though a broad closed low could eventually
develop...no significant tropical development is currently forecast
at this time. This system should remain south of the upper TX
coastal waters as it approaches the eastern coast of Mexico by
the middle of next week. The light east winds currently over the
area should be strengthening a bit Sun afternoon as the wave moves
into the central Gulf. Also be on the lookout for increased
swells, rain chances over the offshore waters Sun night into Tues.
Caution flags may be needed at times. Of note for the bump in
visitors at area beaches this hollday weekend...the risk of rip
currents along area beaches will increase during that time period
as well so use the usual precautions: swim near a lifeguard, away
from rocks, jetties, piers. San Luis Pass is always a dangerous
place to swim. 41
TROPICAL...
Hurricane Dorian has spectacular structure on satellite imagery.
Just pick a GOES 16 channel and be amazed. Forecast track takes
Dorian towards Florida and then curving to the north. We are
watching a tropical wave and weak area of low pressure over the SE
Gulf of Mexico as noted by NHC in the outlook. Model guidance
keeps this as a weak area of broad low pressure as it moves west
across the Gulf with impacts if any being higher rain chances
along the Gulf and slightly higher surf. Mainly this is just
something to monitor Monday through Wednesday next week.
Overpeck
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 75 96 74 99 76 / 20 10 0 10 0
Houston (IAH) 76 97 77 97 78 / 20 10 10 10 10
Galveston (GLS) 81 91 83 90 82 / 10 10 20 30 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...24
Aviation...43
Area Forecast Discussion
National Weather Service Blacksburg VA
1008 PM EDT Sat Aug 31 2019
.SYNOPSIS...
Mostly dry weather and seasonal temperatures are expected for
the majority of the Appalachians and central mid Atlantic
region through early next week as high pressure remains over
the area. However, it remains to be seen if Hurricane Dorian
will track far enough westward to have any effects on our
weather later next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 1000 PM EDT Saturday...
WSR-88D radars showed cluster of showers and thunderstorms over
the Greenbrier Valley and Alleghany Highlands. Overall trends
was for slow weakening and a gradual north-northeast drift. A
bulk of the Hi-Res, ConsShort, SREF, and HRRR diminish the
areal coverage of the precipitation enough after 06Z/2AM to
remove any remaining probability of precipitation after that
time. Only minor changes to minimum temperatures based on
current temperature trends and the latest LAV/MAV guidance.
High pressure wedging down from New England will continue to
push the frontal boundary through the region. This will generate
some low clouds and fog late tonight into early Sunday morning.
Anticipate Sunday will remain dry for the vast majority of the
area with maybe an isolated shower well north if Interstate 64.
Expect lows tonight a few ticks warmer than last night with
low/mid 60s east of the Blue Ridge and generally mid 50s/lower
60s to the west. Highs in the wedge on Sunday will be cooler as
well with middle 80s east to mid 70s/near 80 west.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 300 PM EDT Saturday...
No significant weather hazards expected for our forecast area
during the short term. A weak upper level trough over the region
Monday is forecast to lift northeast and off the New England
Coast, subsidence increasing Tuesday in advance of the tropical
cyclone to our southeast. There is a slight chance for a
shower/thundershower over the mountains Monday, associated with
the trough, but increasing subsidence should put a lid on things
by Tuesday with little or no rain anticipated.
Temperatures Monday are expected to reflect the seasonal norm with
Highs ranging from the 70s mountains to mid 80s piedmont, and Lows
in the 50s mountains to the mid 60s piedmont. Tuesday is expected
to be a few degrees warmer...more sun and subsidence contributing to
the warming.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 315 PM EDT Saturday...
Upper ridging over the southern Rockies and into the southern
Plains, and western Atlantic Ocean, will help to funnel Hurricane
Dorian northward near/along the Atlantic coast Wed-Fri. As troughing
in the northern stream swings through the Great Lakes Wednesday, it
will begin to tug Dorian northeastward near/along the Carolina coast
as additional height falls push through Ontario by Friday. This
suggests the overall impact to our forecast area from Dorian will be
limited, with the end result favoring a dry forecast as opposed to a
tropical deluge. That said, will continue to entertain at least a
chance for some rain associated with Dorian in our far eastern CWA
(east of Highway 29) to account for potential changes in the
forecast track. In addition, the trough which is expected to move
across the Great Lakes Wednesday, will also provide as a lifting
mechanism for showers, so the shower threat may not be just limited
to the eastern CWA, and will entertain at least low chance pops
areawide for Thursday to account for both systems (the trough and
the Hurricane). After Thursday, think the trough will move to the
coast and limit the westward influence from the tropics, confining
the rain threat mainly to the Tidewater region.
The warmest temperatures are expected Wednesday, ahead of the trough
and within the subsidence region in advance of Dorian. Temperatures
are expected to top out in the 80s mountains to near 90 in the
piedmont. The trough should introduce a relatively cooler/drier
airmass for the end of the week, highs/lows retreating to the
seasonal norm, or even a few degrees below that pending cloud
cover.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
As of 743 PM EDT Saturday...
VFR conditions will prevail at the taf site this evening into
tonight with isolated sub-VFR conditions in showers and
thunderstorms for next couple of hours. The best low level
convergence is location north of Interstate 64.
Convection will dissipate this evening with loss of heating.
The front will push southward overnight as high pressure wedges
down from New England. This will bring a surge of low level
moisture into the region on easterly flow and generate some
stratus/fog toward daybreak. The models are showing the richest
moisture in the northwestern portions of the forecast area.
Anticipate a slow improvement in flight conditions by late
morning/early afternoon Sunday. VFR conditions will
return to all taf sites Sunday afternoon.
Winds will generally be light with no significant impact to
aircraft operations expected.
Medium conditions in ceilings, visibilities and winds during
the taf period.
.Extended Aviation Discussion...
Generally VFR conditions are expected through much of next week,
outside any late night fog and isolated showers. Dorian appears
to be staying away from us in the near future, but forecasts
could change. Aviation interests should monitor conditions along
the southeast through next week.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...MBS/WP
NEAR TERM...AMS/MBS
SHORT TERM...PM
LONG TERM...PM
AVIATION...KK/MBS