Severe Thunderstorm Warning 181, NWS Shreveport, LA

Area Forecast Discussion
National Weather Service Shreveport LA
746 PM CDT Tue Jul 31 2018

.UPDATE...
To change weather type back to Thunderstorms 00-06Z timeframe.

&&

.SHORT TERM...
Well, we are likely to diminish soon after sundown thunderwise,
but still looking good on Sat/Rad and even just a look out the
window to the ENE near Grambling and Farmerville with some little
anvils. Others showers are still right ahead of the front from
Sabine to Grant and LaSalle parishes. No other changes at this
time. /24/

&&

.PREV DISCUSSION... /issued 645 PM CDT Tue Jul 31 2018/

AVIATION...
For the ArkLaTex, fropa working past KLFK/KMLU attm with still a
few showers S of KELD moving SE16KT. SFC winds will keep N/NE this
cycle generally less than 10KT. There could be some patchy BR
around daybreak at a few sites with freshly wet soil. Otherwise
Chamber of Commerce start to the new month with dry weather
becoming hotter once again. /24/

PREV DISCUSSION... /issued 350 PM CDT Tue Jul 31 2018/

SHORT TERM...
Upper low has moved ne into Illinois, cold front wrapping south of
I-20 in ne TX, and prefrontal trough has pushed convection mostly
south of cwa as very dry mid lvl air has entrained behind this
trough. Have left in low pops into evening south of I-30 as base
of upper trough associated with the retreating upper low passing
thru area. Temps will fall quickly where dewpoints into the 50s
have moved into ne TX and post frontal cumulus will vaporize
quickly with setting sun. With the front movg very slowly across
remainder of area overnight, expect a variation of overnight lows.
Patchy fog expected across eastern portions of area where clouds
held temps down and dewpoints have not begun to fall. Radiation
cooling with damp ground in places once clouds diminish later this
eveing. Highs tomorrow either side of 90 degrees but virtually no
additional heat index with the low humidity./07/

LONG TERM.../Thursday through Tuesday/

A weak upper level trough will remain nearly stationary Thursday and
Friday across the Mid and Lower MS Valley, but despite the presence
of this feature over these areas through late week, sfc ridging will
maintain a light NNErly and dry low level flow which will keep the
Gulf (and hence low level moisture) cut off and the Ern and Srn
sections of Ncntrl LA dry. The GFS does hint at a weak inverted low
level trough developing Friday over the Lower MS Valley which may
migrate W into NE LA by afternoon, and may focus very isolated
afternoon convection over NE LA which may drift into the extreme Ern
sections of Ncntrl LA. The aforementioned upper level trough remains
progged to drift back W as a shear axis Saturday in response to the
building upper ridge that will begin expanding W across the SE U.S.
from the Wrn Atlantic, with a return of Srly low level winds and low
level moisture resulting in a greater expansion of isolated
convection developing over much of the region. Convection may be
more widely sct over the Srn and Ern zones Saturday and thus have
expanded low chance pops for these areas. Otherwise, isolated mainly
afternoon convection will remain the theme Sunday and Monday as the
weak shear axis is slowly lifted back N and W, trapped atop the SE
CONUS ridge and detached from the Westerlies.

The SE U.S. ridge should begin to flatten out early next week while
the death ridge over Four Corners region begins to amplify and
expand E into the Srn Plains. However, the ECMWF remains more
bullish with the Ewd expansion of the ridge over the Ark-La-Tex than
the GFS, which actually carves a rather deep trough along/E of the
MS Valley by midweek. Not quite buying into this scenario just yet,
but after brief respite from the extreme heat and humidity through
Friday, look for temps to climb back into the mid and possibly upper
90s in most locales this weekend and especially early next week. /15/

PREV DISCUSSION... /issued 133 PM CDT Tue Jul 31 2018/

UPDATE...
Made temp and dewpoint adjustments to reinitialize as portions of
ne TX rapidly rose to near 90 degrees by noon as soon as the
clouds cleared out of the area, but before any cold air advection
settled in. Also removed morning wording, which contained more in
the way of clouds and rain chances./07/

PREV DISCUSSION... /issued 1254 PM CDT Tue Jul 31 2018/

AVIATION...
Convection becmg more isold as moisture becmg more shallow. Left
in another two to three hours at klfk, keld, and kmlu, along with
mvfr cigs near convection. Northerly winds today with prefrontal
trough, otherwise lgt and vrbl until cold front wrapping into ne
TX maintains lgt north winds into night and Wed mrng. Klfk, kmlu,
and keld may see some low clouds and fog overngiht due to wet
ground and lower daytime highs coupled with a slower cooling of
dewpoints overnight./07/.

PREV DISCUSSION... /issued 1113 AM CDT Tue Jul 31 2018/

UPDATE...
Convection across the area has become more scattered with mid lvl
dry air intruding in advance of sfc front, still near I-30. Heavy
rain which ha.SHORT TERM...

.LONG TERM...

&&
s caused overnight flooding across portions of East
TX lakes has fortunately shifted into se TX. Adjusted fcst to
allow for a gradual tapering of pops from the late morning to
early eve period. Have also lowered aftn highs at most locations
due both to the cloud cover south of front and the temp gradient
profile upstream of the front, as do not expect temps to rise more
than 10 degrees at most from late morning readings in either
sector./07/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  68  91  69  93 /  10   0   0   0
MLU  69  89  67  91 /  30  10  10   0
DEQ  61  89  65  92 /   0   0   0   0
TXK  64  89  67  91 /   0   0   0   0
ELD  63  89  65  92 /  10   0   0   0
TYR  66  92  68  94 /   0   0   0   0
GGG  67  91  68  93 /   0   0   0   0
LFK  69  92  68  94 /  10   0   0   0

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&

24/07/15

Hazardous Weather Outlook
National Weather Service Shreveport LA
320 PM CDT Tue Jul 31 2018

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-
TXZ096-097-108>112-124>126-136>138-149>153-165>167-011100-
Sevier-Howard-Little River-Hempstead-Nevada-Miller-Lafayette-
Columbia-Union-Caddo-Bossier-Webster-Claiborne-Lincoln-De Soto-
Red River-Bienville-Jackson-Ouachita-Sabine-Natchitoches-Winn-
Grant-Caldwell-La Salle-McCurtain-Bowie-Franklin-Titus-Camp-
Morris-Cass-Wood-Upshur-Marion-Smith-Gregg-Harrison-Cherokee-Rusk-
Panola-Nacogdoches-Shelby-Angelina-San Augustine-
320 PM CDT Tue Jul 31 2018

This Hazardous Weather Outlook is for portions of south central
Arkansas, southwest Arkansas, north central Louisiana, northwest
Louisiana, southeast Oklahoma, east Texas and northeast Texas.

.DAY ONE...This Afternoon and Tonight...

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday...

Isolated to widely scattered afternoon showers and thunderstorms
will be possible Saturday through Monday across much of the Four
State Region, as low level moisture begins to increase once a weak
upper level disturbance drifts back west across the area. Locally
gusty winds and brief heavy rainfall will be possible in the
stronger storms. Afternoon temperatures will also continue a
gradual warming trend late this week, climbing into the mid 90s
this weekend and early next week. With the increase in humidity
levels expected this weekend, heat indices will range from 100 to
105 degrees through at least early next week.

.SPOTTER INFORMATION STATEMENT...

Activation of emergency management personnel...amateur radio
operators...and storm spotters will not be needed through tonight.

15

Special Weather Statement
National Weather Service Shreveport LA
739 PM CDT TUE JUL 31 2018

LAZ005-010115-
Lincoln LA-
739 PM CDT TUE JUL 31 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LINCOLN PARISH UNTIL
815 PM CDT...

At 739 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles northeast of Arcadia, or 7 miles northwest of Grambling, moving
southeast at 20 mph.

Winds in excess of 30 mph will be possible with this storm.

Locations impacted include...
Ruston, Grambling, Simsboro and Vienna.

LAT...LON 3257 9258 3247 9264 3246 9278 3246 9287
      3257 9288 3260 9288 3261 9287 3265 9286
      3270 9278
TIME...MOT...LOC 0039Z 331DEG 18KT 3260 9282

06

Special Weather Statement
National Weather Service Shreveport LA
745 PM CDT TUE JUL 31 2018

LAZ005-006-010130-
Lincoln LA-Union LA-
745 PM CDT TUE JUL 31 2018

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL UNION AND NORTHEASTERN
LINCOLN PARISHES UNTIL 830 PM CDT...

At 744 PM CDT, Doppler radar was tracking a strong thunderstorm near
Cooley, or 18 miles southeast of Junction City, moving southeast at
15 mph.

Winds in excess of 30 mph will be possible with this storm.

Locations impacted include...
Farmerville, Bernice, Dubach, Downsville, D Arbonne, Bayou D Arbonne
Lake, Shiloh and Unionville.

LAT...LON 3283 9268 3290 9245 3267 9220 3260 9238
      3258 9255 3268 9267
TIME...MOT...LOC 0044Z 329DEG 13KT 3281 9255

06