National Weather Service Raw Text Product

Displaying AFOS PIL: AFDSHV Received: 2019-01-13 02:18 UTC


358 
FXUS64 KSHV 130218
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
818 PM CST Sat Jan 12 2019

.SHORT TERM.../Tonight through Sunday Night/
The latest mid-level analysis indicates a closed low across the
Missouri Valley moving into Illinois this evening. At the base of
this feature, southeastern Oklahoma, southwestern Arkansas, east
Texas, and northern Louisiana are in a zonal flow. At the 
surface, a 1015mb low is located along the Arkansas/Tennessee 
border with a cold front extending southward along the Mississippi
River and into the western Gulf of Mexico. The front has now 
pushed east of our area with winds shifting to west- 
northwesterly and cold air advection (CAA) is evident at 925mb in 
its wake. Behind the front, with the shallow low-level CAA, 
moisture in the 1000-850mb layer is bringing an stratocumulus deck
with ceilings between 1500-2500ft across the area. The cloud deck
currently is covering Oklahoma, east Texas, southwestern 
Arkansas, and northwestern Louisiana and will soon cover all of 
northern Louisiana. 

Overnight, the CAA will continue with the 1000-850mb moisture
completely covering the area. Thus, cloudy skies can be expected
overnight. Despite the low-level CAA continuing overnight, cloud 
coverage and northwesterly winds at around 10 mph will limit 
radiational cooling. Temperatures overnight were in pretty good 
shape with the previous forecast, sticking pretty close to LAMP 
guidance overnight with lows in the mid to upper 30s across much 
of the area. 

On Sunday low-level moisture will bring a cloudy start to the 
day. The big question will be how much will the cloud deck erode 
from the southwest. NAM/GFS both indicate drier air helping erode 
the deck from the south with skies clearing for Lufkin and 
becoming more partly cloudy by the afternoon for Tyler and 
Longview. Elsewhere, it should remain cloudy or mostly cloudy 
across the area. With the cooler air mass and cloud coverage 
across much of the area, this will limit high temps, ranging from 
the mid 40s north of the I-35 corridor in AR/OK/TX to the lower 
50s in east- central Texas and central Louisiana. 

For Sunday night, high pressure will begin to build in from the
northwest with subsidence also helping decrease cloud coverage as
drier air continues to erode low-level moisture from the south.
With this in mind, skies should range from mostly cloudy north of
I-20 to partly cloudy for east-central Texas and central 
Louisiana. /04/

&&

.PREV DISCUSSION... /issued 610 PM CST Sat Jan 12 2019/ 

AVIATION...
In the wake of a cold front, west-northwesterly winds can be 
expected with gusts diminishing across the terminals by 03z. A
cloud deck extending from Ruston to Lufkin will continue to move
southeasterly into Monroe through 03z. VFR ceilings can be 
expected at the onset of the TAF period at Shreveport, Lufkin, and
Monroe with MVFR ceilings elsewhere. Ceilings will drop to MVFR 
across all of the terminals by 06z and continue to prevail 
through 18z Sunday.

As drier air encroaches from the southwest on Sunday, the cloud 
deck associated with low-level moisture will begin to erode from 
the southwest after 18z. VFR will return to Lufkin, Tyler, and 
Longview after 18Z with mostly MVFR prevailing through the day 
elsewhere tomorrow. Winds tomorrow will be lighter at around 10kts
with gusts to 15-20kts in the late morning to afternoon hours. 
/04/


LONG TERM.../Monday through Saturday Night/

Zonal flow aloft will persist, but shortwave ridging and a surface 
ridge of high pressure directly overhead will keep the forecast dry 
until at least Wednesday evening. Below normal temperatures will 
continue on Monday Temps will moderate Tuesday and Wednesday as low-
level southerly flow and warm air advection resume. Rain chances 
will return late Wednesday but will be higher on Thursday as 
isentropic ascent and large scale forcing from a weak shortwave 
trough moving across the Southern Plains spread across the region. A 
weak cold front will also accompany this trough, but will likely 
stall before reaching the forecast area. However, rain chances 
should briefly end across at least the northwest half of the area 
Thursday night/Friday morning as the best ascent moves out of the 
region.

Rapid leeside surface cyclogenesis will occur on Friday in response 
to an upper trough digging southeast from the Central Rockies toward 
the Middle and Lower Mississippi Valley. Scattered showers will 
likely develop once again during the day Friday. The highest rain 
chances should be Friday evening/early Saturday morning immediately 
ahead of the strong cold front and upper trough. Medium range models 
are in good agreement that a decent piece of cold air will become 
dislodged from Western Canada and will move into the Southern Plains 
with this system. The colder air aloft may provide enough elevated 
instability for a few isolated thunderstorms Friday night. 
Significantly colder temperatures are possible next weekend.

CN

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  37  48  33  49 /   0   0   0   0 
MLU  39  49  35  49 /   0   0   0   0 
DEQ  33  44  30  49 /  10   0   0   0 
TXK  36  45  31  46 /  10   0   0   0 
ELD  37  48  32  49 /  10   0   0   0 
TYR  36  47  32  49 /   0   0   0   0 
GGG  36  48  33  49 /   0   0   0   0 
LFK  36  51  36  53 /   0   0   0   0 

&&

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

$$

04/13