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000 
FXUS64 KSHV 232046
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
346 PM CDT Tue May 23 2017

.UPDATE...
Precipitation continued to develop along and behind the front, as
it near deep east TX and northwest LA with a quick movement to 
the southeast. Increasing instability provided by an upper level
jet streak coupled with plentiful low-upper level moisture, may
result in some of the storm activity to become strong to severe
particularly across deep east Texas. The main threats will be 
large hail and damaging winds. A Severe Watch is in effect until
11 pm CDT. 

&&

.PREV DISCUSSION... /issued 300 PM CDT Tue May 23 2017/ 

DISCUSSION...
A broad UA low across the Northern Plains late this aftn, was 
progressing south-southeast thus resulting in the sharpening of 
southwest flow aloft across the Four-State Region. Embedded in this 
southwest flow aloft is a 90+ kt jet max at 250 mb rounding the base 
of this trough, and moving across the region which is allowing for 
increasing UL diffluence. Looking at the sfc, a cold front has 
impinged upon the FA and located along a kcdh, to a ktxk to a ktyr 
line, with a movement to the southeast. Increased UL support 
provided by the aforementioned jet streak, coupled with 
frontogenetical forcing by the cold front and a rather moist 
atmospheric profile /PWATS of 1.20-1.60 inches/ has resulted in 
isolated showers and thunderstorms, mainly along and behind the cold 
front. The stratus deck has eroded but BKN-OVC VFR CIGS remained, 
further validating the moist atmosphere. Nonetheless, there have 
been breaks in the cloud cover which have allowed temps to warm into 
the 70s. As a result, some daytime destabilization/steepened lapse 
rates has been realized which could aid in a few of the storms 
nearing strong levels and producing small hail. The precip is 
expected to not stick around for long, as model solutions displayed 
precip exiting from west to east by tonight, as the UL jet streak 
will be pushing east and hence UL support will be fleeting.   

Overnight, skies are expected to scatter out and perhaps become 
clear across most of the region, whilst relatively light west-
northwest sfc winds ensue. If this does indeed come into fruition, 
this could set the stage for decent radiational cooling and promote 
overnight temps to drop into the upper 40s across portions of 
southeast OK, extreme northeast TX and southwest AR to lower to 
upper 50s elsewhere. Tomorrow, as the UA low commence to near the 
middle/lower Mississippi Valley, the ARKLATEX will be on the 
backside of the disturbance and mid-upper level atmospheric drying 
will occur. However, southwest AR and northeast LA will be the last 
areas for the drier air to take effect, so a few lingering showers 
nearing/brushing across the said areas can not be ruled out during 
the day tomorrow. Otherwise, slight pressure rises tomorrow aftn 
will result in a tightened pressure gradient, which will lead to 
northwest sfc winds approaching Lake Wind Advisory speeds. Due to 
this close call, will elect to hold off on a Lake Wind Advisory for 
this forecast package and let the midnight shift make the call /and 
see if models continue to show this trend/. Tomorrow night, wind 
speeds will become light and at times variable a few hours after 
sunset, whilst clearing skies take place. This will once again 
result in excellent radiational cooling /and perhaps some patchy 
fog/ leading to tomorrow night temps plummeting into the lower 40s 
across the north to lower 50s elsewhere /or some 10-15 degrees below 
norm/. We continue to undercut model guidance by a few degrees for 
tomorrow night because guidance tends to trend towards climo and in 
this case, it is not representative. On Thursday, srly sfc flow will 
return to the region and the quick passage of UA ridging on Friday 
will result in  temps rebounding into the upper 80s to lower 90s by 
the end of the week into early weekend /some 5 or so degrees above 
normal/. 

Thereafter, long term solutions hint at an UA trough getting carved 
out across the Southern Rockies by late weekend, resulting in flow 
aloft veering from near zonal to the west-southwest across the Four-
State Region. The best UL dynamics will remain north of the region 
closest to the center of the disturbance, but a sfc trough and the 
impingement of another cold front will cause the generation of 
showers and thunderstorms. Furthermore, the front is progged to 
become quasi-stationary across the southern zones which will 
maintain the unsettled wx into early next week. It is too early to 
say with certainty whether or not a severe weather threat will exist 
this weekend, but we will continue to monitor this plausibility.  

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  54  73  52  85 /  60  10   0   0 
MLU  56  73  50  83 /  70  10  10   0 
DEQ  49  72  43  83 /  30  10   0   0 
TXK  52  72  49  83 /  50  10   0   0 
ELD  52  71  46  83 /  70  10   0   0 
TYR  53  75  54  86 /  40   0   0   0 
GGG  53  73  52  87 /  40   0   0   0 
LFK  56  78  54  89 /  60   0   0   0 

&&

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

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