Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 231200

Area Forecast Discussion
National Weather Service Shreveport LA
700 AM CDT Fri Mar 23 2018

For the ArkLaTex, clouds are developing ahead of schedule with
middeck overhead and low MVFR cigs into KTYR already and scattered
at other E TX sites. Sfc winds are calm and light SE, but will
pick up in a hurry with heating and mixing. Climb winds light SE
and quickly veer to S/SW at 25-35KT by 1 and 2kft. The SW flow
continues above and is NW 30-50KT for flight levels. While the
clouds increase rainfall should hold off for while with a weak
cold front approaching from N, but falling short of passing. /24/


.PREV DISCUSSION... /issued 320 AM CDT Fri Mar 23 2018/

Tightening pressure gradient across the Southern Plains/Lower
Mississippi Valley will result in Lake Wind Advisory criteria
likely being met across the western 2/3rds of our region today
and therefore have posted this headline with the advisory beginning
at 15z and continuing through 00z this evening. This all due in
part to sfc cyclogenesis in the lee of the Rockies and high
pressure across the southeast Conus. This strengthening southerly
flow will result in increased moisture as well with IR Imagery
already showing increasing low level cloud cover just to our west
early this morning. Thus, should see this cu field expanding into
our region as we go through the day. Looking aloft, upper ridging
will begin to flatten late today into the overnight hours across
the Southern Plains in response to a deepening trough across the
Pacific Northwest. A weak disturbance across the Central Plains
will allow for a cold front to move into eastern Oklahoma Saturday
morning but the airmass in the wake of this boundary is shallow
and thus it will likely remain hung up in the Ouachitas to our
north and west during the day Saturday. With the upper level ridge
flattening across the Southern Plains by late weekend, there is a
chance this boundary could backdoor into southern Arkansas into
northeast Louisiana during the day Sunday before returning back to
the north Sunday Night into Monday. Thus, have kept small pops
going across our northern and northeastern zones Sat and the I-20
Corridor northward for Sat Night thru the day Sunday. By Sunday, a
weak disturbance embedded in increasing southwest flow aloft
could ignite more in the way of scattered showers and
thunderstorms across the Middle Red River Valley of Northeast
Texas, Southeast Oklahoma and Southwest Arkansas and having said
that, have raised pops to high end chance variety for portions of
this region Sunday and again for Monday.

Confidence is growing next week in a widespread heavy rainfall
event shaping up initially along and northwest of the I-30
Corridor of Northeast Texas, Southeast Oklahoma and Southwest
Arkansas Mon thru Wed of next week with that heavier axis of
rainfall shifting south and east of the I-30 Corridor Wed into Thu
of next week. Have weighted next weeks forecast on the slightly
slower timing of the latest 00z ECMWF even through it`s amounts
are likely several inches underdone as opposed to the quicker 00z
GFS. Both of these Medium Range Progs depict a longwave trough
moving out of the Pacific Northwest and into the Intermountain
West before the trough cuts off across the Southwest Conus Tuesday
before opening back up again during the day Wednesday as it
approaches the TX Hill Country. Flash flood Watches may become
necessary as early as Monday for our northwest zones with those
watches likely becoming necessary further south and east
encompassing the remainder of our region as the week goes on.
Widespread rainfall amounts of 4-8 inches will be likely with this
event through next week with isolated higher amounts, especially
north and west of the I-30 Corridor which will result in many of
our area lakes, rivers and bayous once again going into flood.
It`s way too early to predict just how high these tributaries will
go as that will obviously be heavily dependent on which basins
catch the most rainfall. Thus we will continue to hit the
potential widespread nature of this heavy rain event and
concentrate on the individual basins as the event nears.

Thanks for the coordination this morning LZK and WPC, prelims to


SHV  81  62  80  63 /   0  10  10  20
MLU  81  60  81  62 /   0  10  20  20
DEQ  74  57  78  58 /  10  20  20  20
TXK  78  60  77  59 /   0  20  10  20
ELD  80  59  76  58 /   0  20  20  20
TYR  79  64  80  63 /  10  10  10  20
GGG  80  63  80  62 /   0  10  10  20
LFK  82  62  83  64 /   0  10  10  10


AR...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for ARZ050-051-059-060-070-071.

LA...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for LAZ001-002-010.

OK...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for OKZ077.

TX...Lake Wind Advisory from 10 AM this morning to 7 PM CDT this
     evening for TXZ096-097-108>112-124>126-136>138-149>153-165-



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