Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 040527

Area Forecast Discussion
National Weather Service Shreveport LA
1227 AM CDT Wed Oct 4 2023

...New AVIATION...

Issued at 837 PM CDT Tue Oct 3 2023

Radar presentation this evening continues to show light precip
returns with an occasional pulse or two of higher dBZ values
mainly near the developing warm front across the S/SW zones of
the FA. Low to mid level cloud deck associated with the moisture
return behind the developing boundary will continue to advect
northward overnight, helping to put a lid on any radiational
cooling as seen in previous nights under the mostly clear to
completely clear skies. 04/00z SHV sounding this evening
advertised an impressive 0.73" 12-hr increase in PWATs when
compared to the 03/12z sounding this morning. Area PWATs
currently sit between 1.5-2" this evening per recent mesoanalysis
and area soundings. KSHV 04/00z sounding reporting 1.64" in the
PWAT category.

Elected to increase the overnight PoPs across the western third
of the FA as light precip may be possible as the 850mb jet begins
to mature overnight in this region ahead of steadier convective
showers and developing thunderstorms across the same area just
before or shortly after sunrise on Wednesday. 00z hi-res guidance
this evening and previous 18z solutions continue to show this.
Temperatures continue to remain on track so no changes needed
there at this time.



(This evening through Wednesday Night)
Issued at 311 PM CDT Tue Oct 3 2023

The weakening of an upper ridge in the Northwest Gulf of Mexico is
resulting increasing deep onshore flow. Numerous showers and
thunderstorms have developed in Southeast Texas and are streaming
northward towards our CWA and Deep East Texas. Somewhat weaker
instability and forcing exists across our area, so the convection
should weaken with northward extent, but a few showers will remain
possible through early this evening. There may be a bit of lull
tonight before more precip develops early Wednesday.

A deep, long-wave trough currently moving through the Rockies will
emerge into Southern Canada and the Northern U.S. Plains by
Wednesday morning. The eastward progression of this trough will
slow as it becomes more positively-tilted and as an embedded
shortwave strengthens over the Southern Rockies. Strong large
scale forcing should tap into a rich plume of subtropical moisture
resulting in widespread showers and thunderstorms along a strong
cold front from West Texas northeast into Oklahoma and Kansas.
Even though the front will still be well to the northwest,
strengthening onshore flow and warm air advection should lead to
the rapid development of scattered to widespread convection
Wednesday morning across Southeast Oklahoma, Southwest Arkansas,
and most of East Texas. There remains quite a bit of uncertainty
regarding eastward extent of the precip during the day Wednesday,
but some rain will be possible in extreme Northwest Louisiana.

Large scale forcing will rapidly as the southern shortwave trough
and cold front edge farther southeast towards the area. A 35-kt
southerly low-level jet should also increase the coverage and
intensity of the rain. Heavy rain will be likely at times along
and north of Interstate 30. There is still some uncertainty
regarding the exact placement of the axis of heaviest precip, but
a Flood Watch may become necessary for portions of our
northwestern zones in later shifts.



(Thursday through next Monday)
Issued at 311 PM CDT Tue Oct 3 2023

Showers and thunderstorms will become even more widespread across
the entire forecast area during the day Thursday as the upper
trough axis and southern shortwave move eastward across the
Southern Plains. There is quite a bit of model disagreement
regarding the duration of PoPs. The GFS and NAM are rather quick
to end the precip compared to the ECMWF and NBM. The somewhat slow
movement of the synoptic features and the presence of the 850 hPa
front across the CWA suggest rain chances should linger late
Thursday and into Friday across Louisiana and Deep East Texas.
While I favored the NBM and ECMWF, I still felt the NBM PoPs were
a bit too aggressive in the wake of the surface front, so I
undercut them slightly. The rain should largely exit the area
completely by late Friday afternoon. Total rainfall amounts may
be as high as 3 to 5 inches along and north of Interstate 30.
Isolated higher amounts in excess of 6 inches may occur in
portions of Southeast Oklahoma and adjacent areas of Southwest
Arkansas. Most of this rain will occur Wednesday morning through
Thursday afternoon.

Significantly colder and drier air should finally filter down
into the area late Friday and into the weekend. Fall weather is
finally here. Overnight/morning lows Saturday-Monday may be
downright chilly. Most locations will cool into the 40s Sunday
night. Daytime high temperatures this weekend may only warm into
the lower to mid 60s for much of the area north of Interstate 20
Saturday and Sunday.



(06Z TAFS)
Issued at 1215 AM CDT Wed Oct 4 2023

For the 04/06Z TAFs, CIGs will continue to descend through the
predawn hours, reaching lower VFR decks east and MVFR decks west
by 04/12Z, with possibly IFR south and west. Prevailing VCSH
transitioning to SHRA at all impacted terminals, looking to begin
overnight across east Texas airspace, spreading east into the
daytime hours. Southeast winds will continue, becoming more
southerly through the forecast period at sustained speeds of 5 to
10 kts with gusts of up to 15 kts possible.



SHV  87  71  80  67 /  60  70  80  50
MLU  91  69  83  66 /  10  30  50  40
DEQ  79  64  77  60 /  90  90  80  30
TXK  81  66  75  63 /  80  90  80  40
ELD  81  65  75  63 /  40  60  80  50
TYR  84  71  79  67 /  80  90  80  30
GGG  85  68  79  66 /  80  80  80  40
LFK  87  70  81  67 /  70  60  80  40




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