FXUS64 KFWD 250518 AAB
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
1218 AM CDT Wed Apr 25 2018
By midnight, a cold front had entered northwestern portions of
North Texas. The boundary has advanced much further south on the
higher terrain of West Texas where renewed convection has
developed along the I-20 corridor near Abilene and Sweetwater.
With a surface low not far from the Bowie cornerpost, the front
within North Central Texas will take the rest of the night to
reach the Metroplex TAF sites. In the meantime, a small cluster of
thunderstorms that originally developed near the boundary/low is
approaching the Metroplex and may impact the TAF sites during the
nocturnal minimum of traffic.
After the front passes around daybreak, moisture underneath the
frontal inversion should assure MVFR ceilings throughout the
daylight hours Wednesday. The upper trough now on the High Plains
of Nebraska/Colorado will arrive from the northwest Wednesday
afternoon, resulting in another round of elevated convection.
.SHORT TERM... /Issued 327 PM CDT Tue Apr 24 2018/
/This Evening and Tonight/
Showers and thunderstorms are now developing in West Texas near a
dryline and surface low as a weak upper level disturbances ripples
across the area. A few of these storms may become strong or
severe, and the mean flow is expected to drive these storms east.
As this convective activity approaches North Texas this evening,
it will encounter weakening instability and is expected to weaken
in intensity as a result. However, this activity is not expected
to completely dissipate before it moves into western and
northwestern parts of North Texas this evening. Coverage of rain
is expected to diminish through the night as the activity wanes
and have lowered PoPs overnight to reflect this trend. However,
the low PoPs still cover a large area including our eastern
counties due to uncertainty in how far east the rain will progress
Through the night, generally light east winds are expected with
increasing cloud cover. A cold front will enter the northwestern
corner of the CWA an hour or two before sunrise, but strong warm
air advection is not expected ahead of this front. Overnight lows
will be in the 50s and lower 60s with the cooler temperatures
expected where it rains across our northwestern counties.
.LONG TERM... /Issued 327 PM CDT Tue Apr 24 2018/
/Wednesday through next Tuesday/
Our next cold front will be entering our far northwestern
counties at the start of the period on Wednesday morning with
showers and perhaps an embedded storm or two in the post-frontal
air. This front should arrive across the Metroplex during the
mid-late morning hours, delivering a quick northwest wind shift,
effectively stunting any more warming. As a result, temperatures
should remain steady or slowly fall into the afternoon here.
Locales across parts of Central Texas will remain ahead of the
cold front until later in the afternoon, and this should allow
temperatures to top out in the upper 70s to lower 80s. As a
result, a fairly pronounced gradient in highs is anticipated from
northwest to southeast across the CWA.
For the Wednesday morning hours, we've confined the highest (60%)
PoPs roughly north and west of an Eastland to Sherman line where
isentropic ascent will be strongest, quickly tapering to slight
chances from near the Metroplex and south. As the core of a
vigorous shortwave tracks along the Kansas/Oklahoma border
Wednesday afternoon, another area of elevated showers and some
thunderstorms should materialize and track southeastward through
the region. Coverage should be good enough for a quick hit of likely
PoPs roughly north of I-20 during this timeframe. With much of the
area in postfrontal air by the afternoon hours, the threat for
organized severe weather is very low, although an isolated
stronger storm can't be ruled out as dynamic cooling facilitates
some steepening mid-level lapse rates along with 25-35 kts of
effective deep layer shear. Small hail would be the main threat
with the most robust and overachieving updrafts.
Shower and isolated storm chances will linger into the evening
hours across the southeastern 2/3rds of the region as upglide will
be slow to diminish, but precip-free conditions will return area-
wide Thursday morning. Overall quiescent weather is anticipated
into the upcoming weekend as North and Central Texas remains under
the influence of persistent northwest flow aloft. The one
exception may be Thursday night as another potent vort max
pinwheels across eastern Oklahoma and into Arkansas, dragging
another cold front through the region. While the atmospheric
column should be fairly parched of moisture in the wake of
Wednesday's cold front, the proximity of the core of the upper-low
warrants an introduction of very low (20%) precipitation chances
north and east of a Decatur to Emory line. Any instability will
be in very short supply, and have limited the wording to just
showers in the official forecast at this time. The parade of cold
fronts will also help hold high temperatures in the low to mid 70s
going into the weekend.
Return flow will commence Saturday night, but the main surge of
Gulf moisture will hold off until Sunday night and into Monday as
the next round of lee cyclogenesis takes place to our north.
Breezy conditions are in store for Monday as the pressure
gradient tightens, helping to pump additional moisture northward.
While most coarse-resolution guidance is painting low amounts of
QPF across our region during this time frame, it looks like any
activity on Monday would just be in the form of hit-or-miss
streamer showers under a strengthening capping inversion.
More widespread showers and thunderstorms could be in store as we
head into the Tuesday-Wednesday timeframe next week ahead of the
next upper-low slated to drop into Arizona/northern Mexico. The
synoptic upper-air pattern depicted by long range ensemble
guidance could become more supportive of typical springtime severe
weather during the middle of next week, but the finer details
obviously remain nebulous at this juncture.
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 60 64 48 74 53 / 30 60 20 5 10
Waco 59 70 50 77 51 / 10 40 40 5 10
Paris 56 61 47 71 50 / 20 70 20 5 20
Denton 56 61 45 74 49 / 30 70 10 5 20
McKinney 56 62 46 73 51 / 30 70 20 5 20
Dallas 60 65 50 75 54 / 30 60 20 5 10
Terrell 58 66 48 75 51 / 30 50 30 5 10
Corsicana 59 69 49 74 53 / 10 40 50 5 10
Temple 60 73 50 77 51 / 10 30 40 5 10
Mineral Wells 57 62 44 75 49 / 50 60 10 5 10
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