Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 171706

Area Forecast Discussion
National Weather Service Shreveport LA
1206 PM CDT Sat Mar 17 2018

Only minor changes made to forecast to account for temperature,
dewpoint, and Sky cover trends mainly over Northeast Texas, SW
Arkansas, and Extreme SE Oklahoma. Other than that, the rest of
the forecast is on track. /20/


.PREV DISCUSSION... /issued 755 AM CDT Sat Mar 17 2018/

Extensive areas of low MVFR cigs with some embedded IFR cigs have
developed and spread N across much of E TX S of the I-30 corridor,
as well as all of N LA and extreme Srn AR, with some additional
Nwd expansion expected this morning to along the I-30 corridor
into SW AR, where a stationary front will reside through the
afternoon. Some slow improvement in cigs is expected by mid to
late morning, with cigs expected to scatter out by early to mid
afternoon S of the front. Sct convection is expected to develop
late this afternoon over N TX along/just S of the front, and
advance E into E TX after 00Z Sunday, affecting the TYR/GGG
terminals through 06Z, before affecting the SW AR/N LA terminals
after 04Z. This convection will result in MVFR cigs and reduced
vsbys, before gradually tapering off from W to E across E TX by
10Z, and across the remainder of the area by midmorning Sunday.
This convection may disrupt the Nwd advancement of MVFR and
possibly IFR cigs N, but believe LFK will see these lower cigs
advect in after 06Z. SW winds 7-10kts today will become Lt/Vrb
after 00Z. /15/

PREV DISCUSSION... /issued 434 AM CDT Sat Mar 17 2018/

At 09z, a dryline was located very close to and along the
Interstate 30 corridor. Not too far to the northwest, a cold front
was located from near Graham TX, to between Sherman and Paris TX,
and northeast into Southeast Oklahoma and Western Arkansas. This
cold front will overtake the dryline today and become stationary
very close to the U.S. Highway 82 corridor. Subsidence from a
passing shortwave ridge and a strong capping inversion should
suppress precip development for most of the day. Despite cloud
cover across much of the area, strong low level warm air advection
should allow for daytime temperatures to once again rise into the
80s across much of the area.

During the afternoon, a strong upper trough currently over the
Pacific Northwest will dig southeast towards the Southern Rockies.
A weak upper disturbance will pass over Texas in the strengthening
southwesterly flow aloft. Model guidance is in fairly good
agreement that this wave will provide enough lift for convective
development across North and Central Texas ahead of a new dryline.
This convection should move east-northeast into portions of
Northeast Texas and generally along the stalled front during the
evening and overnight hours. A few of these storms could be
marginally severe with large hail and damaging winds the primary

As the West Coast upper trough moves into the Rockies, the stalled
surface boundary will move back north as a warm front and large
scale ascent will spread over the area. Convection will increase
in coverage across the entire area through early Sunday morning
and especially by Sunday afternoon. The upper trough and an
associated surface low will move eastward across Southern Kansas
and Northern Oklahoma. The approaching upper trough should result
in an increase in elevated instability as temperatures aloft cool.
This should result in a potential for large hail. In addition,
deep layer wind profiles should become more supportive for
damaging winds gusts. The overall tornado threat appears low, but
cannot be completely ruled out.

A dryline will move across the area by early Monday morning and
will be quickly followed by a cold front. This will end
thunderstorm chances from west to east by mid to late Monday
morning. No additional precipitation chances are expected until
next Friday and into the weekend until the next surface front and
upper trough develop and approach the region. Temperatures should
be cooled back to near climatological norms behind the front
Tuesday and Wednesday followed by a quick warming trend Thursday
and Friday.



SHV  82  62  77  60 /  10  50  70  30
MLU  82  62  76  61 /  10  50  70  50
DEQ  76  56  68  51 /   0  50  70  40
TXK  81  58  69  55 /  10  50  70  40
ELD  80  57  69  56 /  10  50  70  50
TYR  82  63  78  57 /  20  50  70  30
GGG  83  63  78  58 /  20  50  70  30
LFK  86  66  81  61 /  20  30  70  30




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