Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 191727

Area Forecast Discussion
National Weather Service Shreveport LA
1127 AM CST Mon Feb 19 2018

To raise the daytime highs slightly since readings climbing
a little faster than expected. Bumped up the winds a little
for areas outside of the Lake Wind Advisory.


Minor changes to the forecast by raising the daytime highs
for today and increased the winds outside of the Lake Wind
Advisory. No other significant changes made.


.PREV DISCUSSION... /issued 600 AM CST Mon Feb 19 2018/

For the ArkLaTex, a warm front continues well N of terminals now
and cigs already showing signs of breaking up, but still some IFR
briefly here and there. Most will see MVFR lift to VFR 15-18Z. Big
story is the wind in the warmer regime with S10-20G30KT for most
sites this afternoon. Overnight gustiness will slack, but sustain
still 10-15KT. Models show our next cold front approaching with
convection for Tuesday, but VCSH for TXK by 20/06Z. Expect heavy
convection by late Tue West and areawide Wed with slow cold front.

PREV DISCUSSION... /issued 405 AM CST Mon Feb 19 2018/

Low level moisture has definitely made a return to the Four-State
Region this morning, with dewpoints in the 60s courtesy of a
northward propagating warm front. Visibility restrictions have
been intermittent with patchy fog noted across southeast OK and
portions of southwest AR, right on the edge of the warm front.
Have elected to not add a fog mention for this morning`s 12-15Z
period. Concurrently, a line of scattered showers continued to
progress northeastward north of the I-30 corridor, which is due to
an embedded impulse within the southwest flow aloft. The impulse
is just strong enough to generate a few intermittent thunderstorms
as occasional lightning has occurred.

A broad UA low across the northwest Pacific is poised to shear out
to a longwave trough whilst translating east-southeastward across
the Rockies today through tomorrow, thus sharpening the southwest
flow aloft. Ensuing southerly sfc flow will maintain the
transport of rich Gulf moisture which will result in PWATs surging
to between 1.00-1.60 inches by tonight /highest PWATs noted
across the western 2/3rd of the CWA. This moisture axis coupled
with weak embedded impulses within the flow aloft will allow
showers and thunderstorms to endure across portions of northeast
TX, southeast OK and southwest AR through tonight.

PWATs will surge further by tomorrow aftn /rising to between
1.00- 1.75 inches/ and this will directly result in the
development of moderate rainfall impacting the aforementioned
areas. In addition, will see light rainfall spread to the
remaining FA by this time. Tomorrow evening/night however, is
when the UA troughs cold front will commence to move in from
northwest to southeast and thus provide a linear focus for precip.
Model solutions are insistent that as PWATs near 1.80 inches
coupled with the frontogenetical influence by the cold front,
will aid in the development of moderate to heavy rainfall tomorrow
night-Wednesday morning. Heaviest rainfall during this time
period appears to be located from portions of east TX to across
northeast TX, southeast OK to across southwest AR and northwest
LA. The cold front is not exhibited to be a fast mover and as
such, moderate to possibly heavy rainfall will endure into
Wednesday evening-night with the focus shifting to across northern
and northeast LA to across southwest AR. By Thursday morning, the
cold front is shown to have almost moved south of the CWA but
will quickly retreat back across the region as a warm front, hence
maintaining a wet period /albeit not in the way of heavy
rainfall/. By Friday, the best precip will have shifted to
northern zones closest to the warm front.

Light to moderate rainfall will continue into the weekend as UA
troughiness "reloads" across the western CONUS, which will allow for
southwest flow aloft to persist. The rainfall will finally come to
an end from north to south by late weekend/early next week, once the
the UA disturbance shifts east of the region and the propagation of
its associated cold front allows for the ushering of a drier
airmass. The Weather Prediction Center has a 7 day rainfall total of
the following: 8.00-10.00 inches across portions of northeast TX,
southeast OK to across southwest AR, 6.00-8.00 inches across
portions of east TX, the majority of northeast TX, southeast OK to
across southwest AR, 4.00-6.00 inches across portions of east TX,
northwest LA to across southwest AR, 3.00-4.00 inches across deep
east TX, central LA to across northeast LA and less than 3.00 inches
elsewhere. This could result in poor drainage/low lying roadways
becoming covered by water, ponding of water along streets and water
rises for areas rivers and lakes. We can not stress enough that if
you encounter water covered roadways to Turn Around Don`t Drown and
take an alternate route. Please stay alert to the forecast in the
coming days because if the front is a bit faster than originally
anticipated, these rainfall amounts could lower. The vice-versa is
also true that if the front is slower than anticipated, these
rainfall amounts could rise. Lastly, the threat of severe weather
is low given unimpressive MUCAPE but not negligible due to
adequate 0-6 km bulk shear.

Temperatures will be at its warmest today and tomorrow /70s pushing
the 80 degree mark for some locations/ given the presence of warm
airmass and breezy southerly winds. In fact, wind speeds of 15-25
mph are expected to occur today across all of the Four-State
Region with the exception of portions of central and northeast LA
and portions of southwest AR. This has led to the issuance of a
Lake Wind Advisory valid from 9 AM-6 PM. Temperatures could flirt
with record-breaking warmth today. The onset of widespread
rainfall and the impingement of the cold front by Wednesday will
lead to temps falling into the 50s-70s /70s across central LA
where the front has not yet arrived/, and into the 50s and 60s by
Thursday. The return of the warm front on Friday will allow for
temps to quickly rebound into the 60s and 70s, and will endure
into the weekend. /29/


SHV  81  64  80  65 /  10  20  60  80
MLU  80  64  83  67 /  10  10  20  40
DEQ  75  61  74  50 /  50  60  90  90
TXK  77  63  76  58 /  20  30  70  90
ELD  79  63  81  63 /  10  20  40  80
TYR  77  65  75  57 /  20  30  90  90
GGG  80  64  77  62 /  20  30  60  90
LFK  81  65  78  66 /  10  20  60  80


AR...Lake Wind Advisory until 6 PM CST this evening for ARZ050-059-

LA...Lake Wind Advisory until 6 PM CST this evening for LAZ001>005-

OK...Lake Wind Advisory until 6 PM CST this evening for OKZ077.

TX...Lake Wind Advisory until 6 PM CST this evening for TXZ096-097-



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