Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 111120
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
520 AM CST Wed Dec 11 2019

.AVIATION...
VFR conditions will continue through the 11/12Z TAF period. The back
edge of an extensive stratus shield with IFR cigs over Deep E TX
and the Srn sections of Ncntrl LA will continue to shift SW into
SE TX/Cntrl and Srn LA this morning, scattering out and exiting
the LFK terminal between 12-14Z. Once these cigs clear the region,
SKC will prevail for the remainder of the day, before areas of
thin cirrus begin to increase across portions of NE TX/SE OK/SW AR
after 00Z Thursday. ENE winds of 3-6kts today will become Lt/Vrb
or light SE after 00Z. /15/

&&

.PREV DISCUSSION... /issued 401 AM CST Wed Dec 11 2019/

SHORT TERM.../Today through Wednesday/

The morning RGB 12.3-10.35u satellite imagery indicates that the
back edge of the stratocu field continues to make gradual but
steady progress SW across Lower E TX/Ncntrl LA, with the 00Z NAM
having initialized a bit too slow with the progression out of the
CWA this morning. Based on the current extrapolation, these cigs
should clear the region shortly after daybreak, as sfc ridging
extending from the Mid MS Valley SW through AR into N TX this
morning continues to build farther S into the region. Even with
ample insolation, max temps will remain below normal today, and
have continued to trend with a blend of the NBM and MOS, but did
bump temps up a tad across SE OK/SW AR, as the NBM maintains a
cool bias for these areas with the lack of cold advection and
ample insolation expected today. With the dry air mass in place,
temps should quickly fall under nearly ideal radiational cooling,
and thus have trended min temps a bit below guidance to account
for this. Could see some thin cirrus begin to advance E into
portions of NE TX/SE OK/SW AR tonight, but this should remain thin
enough not to influence temps much.

Even though sfc ridging will remain in place over the region
through Thursday morning before slowly sliding E into the SE CONUS
during the day, H925-850 ridging will shift E of the TN Valley,
resulting in a return Srly low level flow which will commence
by/prior to daybreak. Thus, low level moisture advection will
commence, with a sct cu field advancing N into portions of Deep E
TX/Ncntrl LA during the afternoon. Meanwhile, the short term progs
remain in good agreement with a progressive shortwave trough,
analyzed this morning along the CA/NV border, translating E into
the Rockies this evening, before entering the Srn Plains
by/shortly after daybreak Thursday, advancing E across the region
by afternoon. This will tap an increasing cirrus shield late
tonight through much of Thursday, although large scale forcing
will remain weak and the returning low level moisture field too
shallow to promote any SHRA development. Thus, have removed pops
across SCntrl AR/Ern sections of Ncntrl LA Thursday afternoon,
although the SErly return flow will promote a warming trend with
max temps moderating a bit more than what is expected today, but
still just below normal.

15

&&

LONG TERM.../Thursday Night through Tuesday Night/

A weak shortwave remains progged to shift across the region Thursday
night, but moisture return will be quite meager ahead of this upper
disturbance so have opted to prevail a dry forecast through Friday.
A second upper disturbance will follow by late Friday through Friday
night, but once again it appears the lack of moisture will preclude
any mention of PoPs with just an increase in cloud cover to account
for these passing features. Temperatures will generally run near to
slightly above seasonal averages through the end of the work week as
light southerly flow is expected to return on Friday.

The upcoming weekend also looks warmer and mostly dry with the upper
flow pattern becoming more zonal. By late Sunday, a frontal boundary
is expected to begin shifting into our northern zones with isolated
showers possibly developing along and ahead of the front on Sunday
afternoon. Expect showers to increase through Sunday night and then
become widespread by Monday with some embedded thunderstorms likely
as the cold front traverses through the region. Rainfall amounts are
expected to remain less than an inch over much of the region with
the heavier amounts across our SE half where moisture return will be
strongest. Convection will clear from NW to SE from late Monday into
Monday night with this Pacific cold front ushering in sharply cooler
and drier air as temperatures will return near to slightly below mid
December averages through mid week.

19

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  54  33  57  39 /   0   0   0   0
MLU  52  30  56  42 /   0   0   5  10
DEQ  53  28  55  32 /   0   0   0   0
TXK  52  30  55  35 /   0   0   0   0
ELD  52  28  55  35 /   0   0   0   0
TYR  54  34  57  39 /   0   0   0   0
GGG  54  33  57  38 /   0   0   0   0
LFK  57  33  59  41 /   0   0   0  10

&&

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

$$

15



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