Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX

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FXUS64 KFWD 261558

Area Forecast Discussion
National Weather Service Fort Worth TX
1058 AM CDT Sat May 26 2018

Ample instability exists along/east of I-35 thanks to steep lapse
rates in the 850-600 mb layer per this morning`s 12z sounding.
This has allowed isolated showers and storms to develop just east
of I-35, where what appears to be a subtle gravity wave has aided
in localized ascent. Have expanded PoPs and a mention of thunder
westward to I-35 through this afternoon where pop-up showers and
storms will remain possible. Lightning will be the main hazard
with this activity, but some gusty winds will be possible as well,
especially during the afternoon. The rest of the forecast is in
good shape at this time.



.AVIATION... /Issued 700 AM CDT Sat May 26 2018/
/12Z TAFS/

VFR conditions are expected today with all of the morning
precipitation now completely dissipated. While there is a low
chance of additional thunderstorms this afternoon well southeast
of the major airports, no significant impacts are expected at this
time. Light southerly winds will become more easterly later today.
VFR conditions are expected tonight and Sunday.



.SHORT TERM... /Issued 331 AM CDT Sat May 26 2018/
/Today and Tonight/

Scattered thunderstorms continue mainly east of I-35 this morning
within a broad area of mid level ascent and steep mid level lapse
rates. The 00Z FWD sounding showed that most of the moisture is
located above 850mb with generally dry conditions beneath,
suggesting that this convection is fairly high based with some
limited wind potential. These showers and storms will continue
southward and should weaken as mid level flow weakens through the
morning. The last hour of radar data suggests that this weakening
trend is already underway.

Unlike yesterday where we were on the periphery of the ridge to
the west and the MCS moving out of Oklahoma made a mess of my
forecast, the ridge axis today will actually begin to build into
the region. Strong height rises begin to spread into the region
around midday and continue through the afternoon. In addition, mid
level dry air will also spread into the region from the north.
This should effectively eliminate any chances for additional
thunderstorms through the day. The only exception may be our far
southeast counties which will still be on the eastern periphery of
stronger height rises and may have a little more moisture to work
with. We`ll keep 20 PoPs confined to that area through this

Otherwise, the heat is on from here on through the foreseeable
future. Highs today should top out in the mid 90s along the I-35
corridor with upper 90s to the west. Areas west of Mineral Wells
will likely be in the 99-102 degree range. Our eastern counties
should remain in the low 90s. Mostly clear skies are expected
tonight with lows in the low to mid 70s.



.LONG TERM... /Issued 331 AM CDT Sat May 26 2018/
/Sunday and Beyond/

Mid-level shortwave ridging will attempt build northward across
the Central CONUS Sunday and into Monday, but this will occur
only gradually as Tropical Storm Alberto and and an upper-low
moving out of the Great Basin temper initial height rises. Still,
500 mb heights will be near mid-July normals, which supports mid
and upper 90-degree highs across most of the region, with near
100-degree readings out west. Through the remainder of the
Memorial Day Weekend, heat index values will top out in the 98 to
103 degree range.

The general theme for the upcoming week will be hot and
(mainly) dry conditions as high pressure attempts to build
northward out of Mexico and supplant itself across the Lone Star
State. Tuesday may actually be a degree or two "cooler" than
Monday as the initial shortwave ridge axis breaks down a hair, but
a slow warming trends looks to commence thereafter. While model
guidance supports the first 100+ degree day at DFW since August
19th, 2017 (Waco`s last occurrence was August 22nd, 2017) on
Wednesday, we`ve tempered highs just a bit, siding more with
ensemble mean guidance for the time being for a few reasons...

Coarse-resolution model guidance indicates that there`s a non-
zero potential for convection to develop along the periphery of
the aformentioned ridge Tuesday through Thursday within the
northern fringes of the New Mexican EML plume with very steep
lapse rates (near +9 C/km by Wednesday). While most indications
point to this activity remaining across Kansas and Oklahoma, I
wouldn`t completely discount the possibility of one or more MCS`s
making a run south of the Red River during this period within the
lingering northwest flow aloft. Even if we remain precip-free
here, these large thunderstorm complexes can take a bite out of
the upward height-tendencies ahead of building ridges and
subsequently impact high temperatures.

Either way, it`s still looking hot this week, with heat index
values exceeding 100 degrees each day into next weekend and the
first week of June.



Dallas-Ft. Worth    97  76  98  75  97 /  10   0   5   0   0
Waco                96  73  98  72  98 /  10   0   5   0   0
Paris               91  71  93  71  92 /  10   0   5   0  10
Denton              96  73  96  72  95 /   5   0   5   0   0
McKinney            93  73  95  71  94 /  10   0   5   0   5
Dallas              96  77  97  76  96 /  10   0   5   0   0
Terrell             93  72  96  72  93 /  10   0   5   0   5
Corsicana           93  73  95  72  93 /  10   5   5   0   0
Temple              95  72  97  72  96 /  10   0   5   0   0
Mineral Wells       99  72  98  71  97 /   5   0   5   0   5




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