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789 
FXUS64 KSHV 171000 CCA
AFDSHV

Area Forecast Discussion...CORRECTED
National Weather Service Shreveport LA
500 AM CDT Wed Oct 17 2018

.SHORT TERM.../Today through Thursday/

Areas of -RA continues to develop/shift E generally between the
I-30 and I-20 corridors of E TX, which extends across much of N LA
as well this morning. This is in association with weak convergence
along and N of the H850 trough, as well as weak elevated isentropic
forcing embedded in the SW flow aloft. However, sfc obs indicate
the low cigs beginning to lift across SW AR this morning, as
drying between the bndry lyr and H925 continues to spill SSW into
portions of extreme NE TX to near the AR/LA border. This trend
will continue today with the drier air beginning to deepen late
this morning through the afternoon across portions of N LA and
adjacent sections of NE TX. Convergence along the H850 trough is
expected to weaken later this morning, as drier air continues to
mix SSW, which should result in the areas of -RA diminishing by
afternoon. However, given the current radar trends and the fact
that measurable rain is still falling, have increased pops this
morning to likely along the I-20 corridor of E TX/N LA, tapering
pops down to chance N and S of this area. Have also dropped
mention of pops this morning for SE OK/Nrn sections of SW AR,
although the short term progs are in good agreement with areas of
SHRA currently SW of DFW between MKN and LZZ, lifting NE along a
weak inverted mid level trough into portions of NE TX/SE
OK/adjacent sections of SW AR. These SHRA will encounter a deeper
area of drier air as it approaches the Red River Valley, but still
may result in some light QPF this afternoon. Thus, have retained
low chance pops this afternoon for much of NE TX/SE OK/SW AR/NW
LA, tapering to slight chance elsewhere given that the overall
forcing may tap into the high PW air mass S of I-20 that will
linger through the afternoon. Any sct -SHRA should diminish this
evening as the responsible mid level energy begins to weaken. The
progs also depict weak dirty ridging aloft extending NW across 
much of the area today, as the Wrn Atlantic/Fl Peninsula, and Gulf
of MX ridge begins to bridge W. Should see temps climb about 10 
degrees today as the -RA gradually diminishes and cigs begin to 
lift, and have kept readings closer to the Blends/MAVMOS.

The wedge of low level drier air is expected to continue
backdooring SW across N LA/Lower E TX tonight, although the H850
cigs should not scatter out much farther S than I-20 by Thursday
morning. However, weak overrunning looks to commence by Thursday
morning, in time as a deeper wedge of elevated moisture
originating from the SW Gulf begins to advect N around the Wrn
periphery of the ridge. As a result, isolated -SHRA may develop
across the SW sections of E TX Thursday morning, with the moisture
profile beginning to deepen once again in response to this
moisture advection/saturation from the top down from SHRA
developing/spreading N across Cntrl and Ecntrl TX. Have increased
pops to low chance for the far Wrn counties of E TX Thursday
afternoon given the good agreement in light QPF over these areas,
while also maintaining a buffer of slight chance pops for SE
OK/much of the remainder of E TX. Should see a continued trend of
warming (but still below normal) daytime temps Thursday as well,
with low level moisture advection expected to increase from the S
late Thursday night. This will occur as the closed low indicated 
on the morning water vapor imagery over Nrn AZ this morning, should
begin to slowly lift N into UT tonight, before becoming absorbed 
into the NW flow aloft by Thursday night. This next trough will 
begin to amplify ahead of the next shortwave troughing digging SE 
into the Nrn Plains from Saskatchewan/Manitoba. Thus, overrunning 
and the eventual increase in large scale ascent will begin to 
increase resulting in an increase in SHRA as we round out the end 
of the work week. 

15

.LONG TERM.../Thursday night through Tuesday night/

The very persistant upper level low of late will be located just to 
the North of the Four Corners by late Thursday and is very closely 
modeled by GFS/ECMWF to open wave and slip into the pattern moving 
out across the plains while slowly filing the long wave into a more 
zonal flow across the country by the start of next week. 

However, as expected this will refocus the tropical connection still 
lying across Texas back into our area, initially across I-30 for late 
week. This large area of rain showers will filter down across I-20 
overnight and eventually all of the cwa by mid weekend as a now 
stronger cold front drops down the front range of the Rockies with a 
1032mb air mass over IA by sunset Saturday. The result will be rain 
showers will again work across most of the area Friday and into 
Saturday with fresh Northerly winds that will drive all the moisture 
Southward during the afternoon. 

By far, Sunday is looking to be the much better day this weekend 
with the still 1028mb high centered over KT/TN on and all of the 
rich moisture back in the tropics from Brownsville to Miami. The 
work week starts out dry and below average on temps and now looks to 
continue as such into midweek before the next Pacific cyclone spins 
up South of Baja and looms beyond this scope. Meanwhile, a weak 
upper low will skirt along the Gulf coast from mid to late week, 
keeping primarily just to the South of our area. This is a little 
different than recent days and perhaps a chance for us to dry out. 
/24/

&&

.PREV DISCUSSION... /issued 1149 PM CDT Tue Oct 16 2018/ 

AVIATION...

For the 17/06Z TAF period, IFR/MVFR cigs continue to plague all 
sites this evening as light to moderate rain is still ongoing over
much of the region. Expect these trends to continue through at
least daybreak as cigs may dip even lower with intermittent LIFR 
conditions at times. Rain should began to taper off during the day
on Wednesday, but still cannot rule out some periodic rainy 
periods as SW flow aloft shifts more westerly. Cigs will begin to 
finally improve as well, likely seeing MVFR and some low VFR cigs 
late in the period. N/NE sfc winds will prevail with speeds from 
around 6-12 kts through much of the period.

/19/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  58  55  64  55 /  60  20  10  10 
MLU  58  54  68  55 /  60  10  10  10 
DEQ  62  52  62  52 /  30  20  10  30 
TXK  57  51  62  51 /  40  20  10  20 
ELD  58  51  64  52 /  40  20  10  10 
TYR  56  54  63  52 /  60  20  30  10 
GGG  58  55  63  54 /  60  20  20  10 
LFK  58  56  68  57 /  30  20  20  10 

&&

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

$$

15/24