Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 221726
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
1126 AM CST Wed Feb 22 2017


.AVIATION...
Wraparound moisture on backside of slow movg upper low just
reaching the TX/LA and TX/AR state lines, with KTXK and KSHV
seeing a mix of mvfr and skc for until around 20z with skies
remaining skc thereafter. While ne TX will remain skc thru the
23/18z fcst cycle, remaining terminals may see overnight fog,
especially at KMLU and KELD where clouds well into the aftn
determine daytime heating. However, in either case, expect skies
becmg skc with daytime mixing around 23/15z with an increase in
south winds. These winds may reach around 10 kts over ne TX before
23/18z, and becmg more gusty into the aftn Thu./VII/.

&&

.PREV DISCUSSION... /issued 942 AM CST Wed Feb 22 2017/

UPDATE...
Minor changes made to the current forecast such as increasing
temperatures a degree or two, particularly across east TX, deep
east TX and portions of southeast OK, and northwest LA which is
void of cloud cover. Subsequently had to tweak the relative
humidity values and dewpoint temperatures. Otherwise, the
forecast is largely on track as a warmup is expected later today.

PREV DISCUSSION... /issued 504 AM CST Wed Feb 22 2017/

DISCUSSION...
The morning satellite imagery indicates that our pesky upper low
has finally begun to shift S over Srn MS/SE LA this morning,
although the wrap-around cloud cover continues to linger across
much of AR/N LA/extreme Ern TX. Sfc obs also reveal low stratus
which has developed/trying to spread WSW from Scntrl AR into
portions of Ncntrl LA, with the short term progs suggesting that
the low stratus may linger through early afternoon over these
areas before it begins to scatter out. Should see a pronounced
warmup commence today as the cigs begin to scatter out with the
departure of the upper low into the Nrn Gulf, with much above
normal temps returning to SE OK/E TX/Wrn LA with temps near/just
shy of 80 degrees. A light SSE low level flow will return to the
region this evening, which will become enhanced Thursday in
response to a tightening pressure gradient over the Srn Plains
induced by the approaching shortwave that will traverse the Great
Basin into the Rockies. This will aid in the increase in
warm/moisture advection over the region Thursday, with max temps
climbing well into the 80s over E TX, with these readings just shy
of record territory. S winds should stay up overnight Thursday
ushering in a return to the low stratus late, with min temps not
falling much if not below 60 degrees.

The aforementioned shortwave remain progged to lift NE into the
Midwest Friday morning, with trailing shortwave energy translating ESE
beneath the trough across Srn KS/OK into MO/NW AR late in the day.
This second piece of energy will help reinforce a cold front SE into
the area Friday, with the front clearing the Lower Toledo Bend Country
and Ncntrl LA during the evening. As was the case with our last
frontal system last week, the post-frontal cold advection looks to lag
the front a ways, and have trended max temps near or just below the
much warmer MAV guidance, into the upper 70s/lower 80s. However, much
drier air looks to immediately follow the fropa, resulting in
abnormally low RH`s over E TX/SE OK Friday afternoon. The GFS/ECMWF
continue to depict a lack of deep lyr moisture ahead of the front,
thus have kept the forecast dry through Friday evening with the fropa.

Should see a return to more seasonable temps Friday night through
much of this weekend as Canadian sfc ridging builds S into the Srn
Plains. The protected areas of SE OK/Nrn sections of SW AR could see a
light freeze Saturday night, before a slow warming trend commences
Sunday as srly low level winds return with the departing sfc ridge E
of the lower MS Valley. Low level moisture advection returns in
earnest Sunday night in response to an increasing SWrly LLJ, with
above normal temps expected Monday through the remainder of the
extended as a weak SWrly flow aloft sets up over the Srn Plains ahead
of the next amplifying trough along the W coast that will translate E
across the Great Basin into the Plains by midweek. The remains some
discrepancies amongst the GFS and ECMWF in regards to a potential weak
sfc front that the ECMWF suggests will drift SE before hanging up
Monday near the Red River of SE OK/Wrn AR. Not quite buying this
scenario yet given the deep Swrly flow, and have maintained slight
chance pops Monday/Monday night in response to the increasing
warm/moisture advection. However, these progs do come into reasonable
agreement with the aforementioned shortwave generating considerable
forcing as it Tuesday and Wednesday as it traverses the Srn Plains,
and have maintained mid chance pops for the latter extended. Based on
the shear and instability profiles, this system will need to be
watched closely for our next potential for severe convection.

Prelims to follow below...

15

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  77  54  83  59 /   0   0   0  10
MLU  73  51  79  57 /   0   0   0  10
DEQ  77  49  81  55 /   0   0   0  10
TXK  75  53  81  58 /   0   0   0  10
ELD  74  49  79  58 /   0   0   0  10
TYR  79  55  83  59 /   0   0   0  10
GGG  79  53  83  59 /   0   0   0  10
LFK  79  52  83  59 /   0   0   0  10

&&

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

$$


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