Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 260825
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
325 AM CDT Fri May 26 2017

.DISCUSSION...
Another quiet, and unseasonably warm day will close out the end of
the week, as flattened UA ridging progress overhead. To our west,
near zonal flow aloft will bring with it mid-high level
cloudiness, so expect increasing cloud cover today. A sfc low
across the Panhandles region this morning is progged to push east
to across the Red River Valley region by mid-morning, and produce
a tightened pressure gradient. Despite the cloudiness, model
guidance suggest southerly wind speeds will increase to between
15-20 mph /with higher gusts/ and will therefore elect the
issuance of a Lake Wind Advisory CWA-wide from 26/15Z-27/00Z.
Shortly after sunset, the pressure gradient will relax and
subsequently wind speeds will fall to below Lake Wind Advisory
criteria. It is interesting to note that a few model solutions
exhibited rather light QPF signals across east TX, southeast OK
and southwest AR this aftn, but is likely overdone as a capping
inversion will be in place.

Attention will turn to a positively-tilted UA trough extending from
a closed low across southern Canada to across the Northern Plains
southwest to across the Southern Rockies tomorrow. As the
disturbance gradually pushes east-southeast, it will result in
flow aloft veering to the southwest across the Four-State Region.
The disturbance`s sfc counterpart will provide two boundaries that
will be a foci for thunderstorm development. The first is a
dryline that will surge eastward to across the Red River Valley
region and encourage the development of thunderstorms tomorrow
aftn. The second boundary is a cold front that will propagate
southeastward and near southeast OK and extreme northeast TX late
tomorrow aftn/early evening. Thunderstorms are progged to develop
along and ahead of the cold front. There is a capping inversion
and a bit of drying in the mid-levels of the atmosphere that needs
to be overcome, however model soundings indicated the eroding of
the cap and a moistening atmosphere /PWATs increasing to between
1.50-1.80 inches/ by tomorrow evening/night. As a result, it
would not be surprising to see isolated-scattered showers and
thunderstorms affect extreme northeast TX and southeast OK
tomorrow late aftn/early evening, with scattered to numerous
storms occurring by tomorrow evening/night especially across the
northern zones. MUCAPE of 3000-4000 j/kg coupled with 0-6 km bulk
shear of 40-50 kts suggest storms capable of becoming strong to
severe, with large hail and damaging wind gusts being the primary
threats. Best severe indices are across the northwest zones
tomorrow evening/night, associated with the impingement of the
cold front. Furthermore, 0-1 km helicity values of 200-300 m2/s2
and a veering hodograph in the low levels implies isolated
tornadoes can not be ruled out. High PWATS will lead to the
potential for the storm activity to also produce moderate rainfall
for some locales. The cold front will continue to progress
southeastward and be located south of Interstate 20 by Sunday,
where it will become quasi-stationary. Early next week, the front
will return as a warm front and a series of UA shortwaves or
embedded impulses will maintain an unsettled wx pattern
throughout the week, resulting in a wet ending for the month of
May.

The bouts of rainfall and cloudiness will cause daytime temps to
drop from the upper 80s to lower 90s of today-Saturday, down to
the lower 80s by next week, and prompt overnight temps to fall
from the lower to middle 70s to the 50s and 60s.


&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  89  75  91  74 /   0  10  10  20
MLU  90  73  90  73 /   0  10  10  20
DEQ  86  72  88  71 /  10  10  10  50
TXK  87  73  90  72 /  10  10  10  40
ELD  89  73  88  72 /   0  10  10  30
TYR  89  76  90  74 /  10  10  10  20
GGG  89  76  91  74 /  10  10  10  20
LFK  89  77  93  77 /  10  10  10  20

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for ARZ050-051-059>061-070>073.

LA...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for LAZ001>006-010>014-017>022.

OK...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for OKZ077.

TX...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for TXZ096-097-108>112-124>126-136>138-149>153-
     165>167.

&&

$$

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