Forecast Discussion for Dallas/Ft. Worth, Texas

FXUS64 KFWD 260008 AAA

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
708 PM CDT Fri May 25 2018

We are keeping an eye on an area of storms that is between
between KLBB (Lubbock) and KFDR (Frederick, OK) as of 25/2350z.
These storms are moving southeast at about 20 knots in the
northwesterly flow aloft. If this activity holds together, it
would reach the Metroplex TAF sites 05-06z. Expect VFR and rain-
free weather through this evening with southeast winds around 10
knots. Have put VCTS in starting at 04z with a TEMPO TSRA for the
05-08z period. VFR with NSW (No Significant Weather) is expected
after 09z. Southeast winds around 10 knots will persist through
04z with winds then becoming more southerly.

At Waco, an outflow boundary moved through around 25/2230z. VFR
and rain-free weather is expected through this evening. There is a
low chance of showers and thunderstorms overnight, so have left a
VCSH in for the 08-14z period. The chances of thunderstorms were
not high enough to even include TSRA, but that will be updated
with the 03z or 06z TAFs issuances if storms look more likely.
Southeast winds around 10 knots will prevail with winds becoming
southerly by 08z.



.SHORT TERM... /Issued 303 PM CDT Fri May 25 2018/
/Through Tonight/

Main focus through the short term continues to be thunderstorm
potential through this evening and overnight. This morning`s
complex of storms continues to move southeast and is largely
confined to areas east of I-35. New development has struggled to
initiate to the west due to some weak capping where outflow has
now surged ahead of the complex. However, the environment remains
quite unstable ahead of this boundary, and convergence along it
should support the initiation of isolated/scattered storms by
late afternoon as CIN continues to erode. Some indications of
destabilization are present with an increasingly agitated cumulus
field from roughly Graham to Granbury. Any storms that do develop
in the outflow`s vicinity will have a threat for strong downburst
winds due to the presence of significant DCAPE and theta-e
differences of nearly 25-30K from the surface through the
mid-levels. This activity would largely be diurnally driven, and
should weaken after sunset.

Our eyes will then turn to the north, where additional convection
is expected to develop across the Texas Panhandle and western
Oklahoma late this afternoon and evening. High-res models have
persistently indicated a rather robust MCS diving southward into
North Texas from this would-be activity. However, many of these
models are also largely unaware of the existence of convection
this morning, making their subsequent forecasts quite
untrustworthy. The environment in which this batch of storms is
forecast to develop is still largely capped at this hour, although
there finally has been some growth of cumulus southeast of
Amarillo. This will be the area to watch through the evening, as
development of thunderstorms and evolution into a complex would
likely mean another round of storms for North Texas late this
evening and overnight with propagation vectors suggesting a due
southward motion. This morning`s convection has only acted to
lower confidence in this forecast however, and storm
development/longevity remains in question. If a complex of storms
was to materialize and move into North Texas from the northwest,
it would pose a severe wind threat as well as the potential for
small hail. Have maintained low PoPs in the forecast with rather
low confidence in how tonight`s convection will play out.



.LONG TERM... /Issued 303 PM CDT Fri May 25 2018/
/Saturday through Friday/

North and Central Texas will remain in northwest flow aloft on
Saturday. Any convection that manages to develop north of the Red
River overnight will move southeast across the region Saturday
morning. Since the atmosphere will remain very moist and unstable,
there will be a potential for brief heavy rainfall and gusty
wind. We anticipate that storms will move southeast of the area
before midday Saturday but some lingering outflow boundaries could
spark new convection in the afternoon so will leave some low PoPs
in place.

Upper level high pressure will build over the region Saturday
night through early next week while subtropical storm Alberto
gathers strength in the eastern Gulf and an upper low spins its
wheels over the Great Basin. Increased subsidence will result in
hot temperatures and very little chance for storms. Afternoon
highs Sunday and Monday will be generally in the 90s but should
reach the century mark across the western zones. Since abundant
low level moisture will remain in place, afternoon heat index
values will reach 100 or just above in nearly all locations.

The upper ridge will deamplify slightly Tuesday through Friday but
will remain largely centered over the state, keeping hot, humid
and rain free weather in place. Afternoon highs will range from
the middle 90s in the east to around 104 in the west. Overnight
lows will remain in the 70s. Afternoon heat index values will
approach heat advisory criteria most of next week, but should stay
just below 105.



Dallas-Ft. Worth    75  95  75  96  75 /  40  10   5   0   0
Waco                73  95  73  96  73 /  30  20   5   0   0
Paris               69  92  71  93  71 /  30  10   5   5   0
Denton              72  96  72  96  72 /  40  10   0   0   0
McKinney            72  93  72  94  72 /  40  10   5   5   0
Dallas              76  96  76  96  76 /  40  10   5   0   0
Terrell             73  93  72  94  72 /  30  20   5   5   0
Corsicana           73  93  73  94  73 /  30  20   5   0   0
Temple              70  95  72  96  72 /  20  20   5   0   0
Mineral Wells       72  98  71  98  71 /  30   5   0   0   0





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