Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 261207

Area Forecast Discussion
National Weather Service Shreveport LA
707 AM CDT Thu Apr 26 2018

For the ArkLaTex, upper low rotating over KMEM with wrap around
MVFR cigs affecting all but our TX terminals where SKC has been
the case. Cigs will lift to VFR w/ heating, but continue over
AR/LA until low moves farther E. SFC winds are W/NW 5 now and 10KT
by mid morning. Climb and flight level winds are also NW, 20-50KT
and 60-80KT 20-30kft. Another weak fropa tonight will keep the
ball rolling on NW flow with another Chamber day really for the
next few w/ low level winds coming around, veering to SE by Sun.


.PREV DISCUSSION... /issued 432 AM CDT Thu Apr 26 2018/

The sct convection has quickly shifted E of the region this
morning, as the water vapor imagery depicts a deep wedge of dry
air has entrained E into Wrn MS, SE of the closed low centered
over Ern AR. However, wrap-around stratocu continues to shift SSE
across the Nrn and Ern half of the region, with the short term
progs suggesting that this cloud cover will expand SSE across the
Ern 2/3rds of the area later today. Evenso, cigs may scatter this
afternoon, resulting in enough insolation to allow max temps to
climb into the upper 60s/lower 70s areawide.

Our focus will again turn upstream to the NW as the next shortwave
trough, depicted from the Nrn Plains SW to Cntrl CO/UT, quickly
drops SE into the Srn Plains by this evening, before shifting E
over the region late tonight. Even though there will not be any
low level moisture advection ahead of this trough, adequate
mid/upper level moisture and the potential for lingering H850
moisture may allow for very isolated -SHRA development late
tonight given the dynamical forcing with this cold core trough,
thus have maintained slight chance pops late tonight, and even
expanded them to encompass the remainder of the region given the
slightly faster model solutions with the trough. However, very
little if any measurable QPF is expected. Also maintained slight
chance pops Friday morning over the Ern sections of Ncntrl LA to
accommodate the potential for isolated -SHRA development before
the trough exits the region by midday, with some residual cu
lingering through the afternoon before drier low level air mixes
Swd in wake of the departing trough. Temps should return to more
seasonal norms Friday as cooler air will not follow the trough
passage, but only reinforcing the dry air mass in place. With sfc
ridging building Swd into the Srn Plains/much of the region Friday
afternoon and night, good radiational cooling is expected with
light winds and a clear sky, setting the stage for possibly one of
spring`s last gasps of cool air before the air mass begins to
slowly modify over the weekend.

Should see temps climb back slightly above normal Saturday with
weak sfc ridging over the area, with a reinforcing sfc ridge
backdooring SW into AR/MS Saturday night. This will have little
if any impact on our sensible weather though, with a SErly low
level flow returning Sunday as this sfc ridge builds ESE across
the TN Valley and SE states. Thus, RH`s will begin to gradually
modify Sunday and especially Monday, with above normal temps
persisting as upper ridging builds E across the MS Valley late
this weekend and early next week.

The upper flow will gradually transition to SW by Tuesday, as an
upper low over the Pac NW broadens out and expands along and W of
the Rockies. Did leave in slight chance pops areawide Tuesday to
account for deepening low level moisture and the potential for
ripples in the SW flow aloft that may help trigger isolated
convection with afternoon heating, although both the ECMWF and
GFS suggest that the upper trough will deepen late
Tuesday/Wednesday over the Desert SW before swinging E in VC of
the Four Corners region by midweek. Although timing discrepancies
with this trough exist during the latter portion of the forecast
period, a more active convective period looks to evolve across
portions of the Srn Plains by midweek, which would suggest that
more in the way of sct convection could spread E into portions of
our region by mid and late week. Did maintain chance pops for the
region for midweek, with refinements likely needed in the coming
days given the evolution of this trough. Very warm and humid
conditions will likely persist through much of next week as well
as we enter the first several days of May.

Prelims to follow below...



SHV  71  54  78  51 /   0  20   0   0
MLU  70  54  77  52 /  10  20  20   0
DEQ  70  49  75  44 /   0  20   0   0
TXK  69  53  76  49 /   0  20   0   0
ELD  70  53  77  48 /  10  20  10   0
TYR  71  54  78  50 /   0  20   0   0
GGG  70  54  77  50 /   0  20   0   0
LFK  75  53  80  51 /   0  20   0   0




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