Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/01/20
Area Forecast Discussion
National Weather Service Fort Worth TX
536 PM CST Sat Feb 29 2020
.SHORT TERM... /NEW/
/Through Sunday evening/
A warm and breezy day today across the region, with winds gusting
upwards of 30 MPH at several of our observation sites.
Temperatures have also soared into the 70s. This strong warm air
advection is occurring in response to cyclogenesis along the lee
of the Rocky Mountains. Aloft, a potent shortwave trough is
digging into the Pacific Northwest. The differential cyclonic
vorticity advection associated with this digging shortwave trough
is aiding in the aforementioned surface cyclogenesis. This pattern
will continue to dominate the weather through the short-term
portion of the forecast.
Tonight, a strong low-level jet (LLJ) is forecast to develop,
with winds of 40+ KT at 2,000 ft AGL forecast by model guidance.
This strong LLJ will transport moisture northward, leading to a
surge of Gulf stratus across the eastern half of the CWA. As is
typically the case, I-35/35W should be the approximate western
boundary of this stratus. A little patchy drizzle will be possible
as well for areas east of I-35/35W, but this would be very light,
with no rainfall accumulations forecast. The gusty southerly
winds will keep the boundary layer well-mixed enough to preclude
any fog development.
The stratus will hang around through the morning hours Sunday, but
should dissipate from west to east as winds veer, and drier air
works its way east. Later in the afternoon, a dryline will surge
eastward. While decent instability will be present with dewpoints
in the upper 50s beneath steep mid-level lapse rates, a very
strong cap will also be in place. High-resolution model guidance
and forecast soundings show convective inhibition (CINH) values
in excess of 100 J/kg, thus without any strong upper-level support
(which we will not have), the warm sector ahead of the dryline
should remain capped. Still, a few models try to generate some
light QPF, and there does appear to be more of a chance for
showers/thunderstorms east of our CWA. For this reason, opted to
include a low mention (including isolated thunder) in our very
eastern fringes. These "conditional" thunderstorm days rarely
produce much if anything at all, but given the strong instability
and modest wind shear that will be present, we will leave the
window open just a crack for that low-end potential for an
isolated thunderstorm.
Godwin
&&
.LONG TERM... /Issued 307 PM CST Sat Feb 29 2020/
/Monday through Thursday/
The start of the work week will be warm with increasing rain
chances toward mid-week. At this point in time, it appears that
widespread rain with embedded thunderstorms are a good bet for
just about all of North and Central Texas. There will be a risk
for moderate to heavy rain which could result in some flooding.
A severe weather risk does exist, but current thinking is that
the window in which this occurs will be very limited (late
Tuesday afternoon/evening) and over a small area (Central
Texas/Brazos Valley). By Thursday, most areas should be largely
rain/storm free with mostly clear conditions thereafter.
Low clouds and drizzle will blanket at least the eastern half of
the forecast area on Monday morning with pretty mild conditions to
start the day. Morning lows will remain in the upper 50s to mid
60s with southerly breezes starting around 5 to 15 MPH. Daytime
mixing should erode the cloud deck from west to east through the
day and this will likely yield another elevated fire weather
threat west of I-35 where winds will become southwesterly and
increase into the 10 to 20 MPH range. Highs will climb 5 to 10
degrees above normal for most of North and Central Texas with
forecast values in the low to mid 70s. Some areas immediately
along the thermal axis may even climb toward 80 degrees.
Rain chances on Monday have been lowered some as it appears that
850mb temperatures close to 14-14.5C are probable and this should
keep a decent sized lid on any deep moist convection. Still, some
showers beneath the cap will be possible, mainly across East
Texas and immediately along the southward advancing cold front.
I`ll add in a mention of isolated storms across East Texas/Brazos
Valley where instability bubbles closer to 1000 J/kg. We`ll need
to reassess the strength of the cap on Monday. If we get a bit
more sun and/or a larger degree of moisture...updrafts may be able
to tap into slightly greater instability. Given that deep layer
shear is projected to be plentiful, there could be a risk for
organized convection.
The better risk for more organized convection will hold off until
Tuesday afternoon/evening, however, as the aformentioned cold
front stalls. Model guidance has slowed the progression of the
upper trough (now slower and deeper) and this will have
ramifications on the frontal position. Regardless of where the
front stalls exactly, locations to the south of this feature will
become modestly unstable. Instability will dwindle with northward
extent from the surface front. Current thinking is that the front
will stall near the US HWY 79 corridor, leaving parts of
Milam...Robertson...and Leon counties in the warm sector and thus
a severe weather risk. Stay tuned as we get a better handle on the
position of the front. Ascent atop this front will lead to
widespread rain and embedded storms through the day on Tuesday and
into Wednesday. Storm total rain amounts range between 1-2"
across the area with the greatest totals right now focused near
and south I-20. Given rainfall tendencies over the last 30 to 60
days...there will likely be some flood potential as PWATs over 1"
should allow for efficient rainfall producers and thus heavy rain
will be a threat. Depending on the overall convective nature of
activity, some flood headlines may be needed (mainly for main-stem
river, lakes and creeks).
Conditions should improve Thursday through the remainder of the
week with temperatures near or just above normal as southerly
flow returns. We`ll see some breezy conditions, but at this point
in time, anticipated rainfall should mitigate any appreciable fire
weather concerns. If rain amounts are underwhelming, we`ll need
to examine this potential again.
Bain
&&
.AVIATION... /NEW/
/00Z TAFs/
Concerns -- Early morning MVFR stratus. Continued gusty S-SWly
winds.
Gusty Sly winds continue across the forecast area this evening,
with most METAR sites reporting gusts of 20-30 KT. Winds will
subside a little overnight, but sustained winds of 10-15 KT with
gusts to around 20 KT will continue.
Later this evening, a strong LLJ will develop, with winds in
excess of 40 KT likely around 2 kft AGL. Low-level flow will be
fairly unidirectional, which should preclude a greater risk for
LLWS, but given the strength of the LLJ, lighter aircraft may
experience some airspeed loss if departing after 03Z. This strong
LLJ will also spread Gulf stratus northward. Expect CIGs at most
TAF sites to drop to MVFR before daybreak, with MVFR persisting
thru around 17-18Z. Strong low-level flow should prevent CIGs from
dropping to IFR, but there is a weak possibility of some
intermittent IFR CIGs at KACT. Opted to maintain MVFR from
previous TAF issuance, but later forecasts may need to address
this potential. All TAF sites should improve to VFR by early
afternoon as increasing S-SWly winds bring in drier air, allowing
CIGs to lift.
Godwin
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 57 75 60 75 49 / 0 0 0 20 30
Waco 57 73 60 75 52 / 0 0 0 10 30
Paris 55 69 60 72 54 / 5 10 5 30 30
Denton 56 77 58 75 50 / 0 0 0 20 30
McKinney 57 73 60 73 54 / 0 5 0 20 30
Dallas 59 75 60 75 56 / 0 5 0 20 30
Terrell 57 73 61 74 59 / 0 5 0 20 30
Corsicana 57 71 62 75 61 / 0 0 0 10 30
Temple 55 72 60 75 61 / 0 0 0 10 20
Mineral Wells 53 79 55 76 48 / 0 0 0 20 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
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