Area Forecast Discussion
Issued by NWS Shreveport, LA
FXUS64 KSHV 231237
Area Forecast Discussion
National Weather Service Shreveport LA
737 AM CDT SAT JUL 23 2016
For the ArkLaTex, SW winds are light on the sfc, but increase to
20kts by 3kft, then are mostly E/NE up to 30Kft. Pretty wet
sounding this morning indicating a weak disturbance aloft will
have ease in making TCU by lunch in a few spots. Aftn TSTMs will
decrease in coverage toward sunset. Downpours will gust the winds
to 30 mph and brief heavy rain will be accompanied by lightning.
Little change until midweek/late week in this wetter p.m. pattern.
MVFR BR will be more likely at more terminals daybreak Sunday.
.PREV DISCUSSION... /issued 555 AM CDT SAT JUL 23 2016/
10z temps still remain near or just below 80 degrees over the
region this morning...with the lack of cloud cover resulting in
another quick rise in temps which should resume shortly after
daybreak. The morning water vapor imagery indicates two separate
areas of upper level ridging...one over Ern NM/W TX...and the
second over the Lower MS Valley. A weak trough aloft was also
noted extending W-E from Nrn AR across TN...and has triggered sct
convection earlier this morning over SW TN. PW/s per the 00Z
regional raobs still range from near to in excess of 2 inches over
much of the region...with isolated to sct convection expected to
develop again by afternoon over the region. Not seeing much of a
focus at the sfc or aloft just yet...with weak shear contributing
to pulse-type convection which will be outflow driven once again.
Have maintained low chance pops for SW AR/N LA this afternoon with
slight chance pops farther W across SE OK/E TX. Given the lack of
morning cloud cover and the proximity of the double barrel ridge
in place from the Srn Plains E into the Lower MS Valley...temps
should again warm quickly...very close to temps observed Friday.
Have had to nudge max temps up a bit today...with the dewpoint
forecast a bit more tricky especially over the Ern zones.
The air mass along the Delta region has been rain cooled from sct
convection which fired over this area Friday afternoon...but the
air mass should recover later this morning with the high PW/s not
allowing for much mixing this afternoon. Some extreme heat indices
were observed for 2-3+ hours across Union County AR into the ern
sections of Ncntrl LA...where readings ranged from 110-114
degrees. While temps should ease up a tad this afternoon...still
could see heat indices of 107-110 degrees...with isolated higher
values briefly possible before the air mass is influenced from
the sct convection that develops by early/mid afternoon. Was
tempted to upgrade the current Heat Advisory to an Excessive Heat
Warning but did refrain for now but after collaboration with
neighboring WFO/s this morning...and the rain cooled air over
these areas...just maintained the Advisory for now with the Day
Shift monitoring for a possible upgrade later this morning.
Elsewhere...heat indices should again range from 105 to 110
degrees this afternoon. Have allowed to Heat Advisory to expire at
00Z this evening as scheduled as cooler temps/sct convection is
expected by Sunday.
The short term progs are in good agreement with the aforementioned
trough over much of TN beginning to close off later today as it
drifts SW into SE AR/NE LA late tonight. This closed off vorticity
center should continue to drift slowly W across S AR/N LA Sunday
and focus more sct to numerous convection over these areas. Have
raised pops to high chance over these areas...with much needed
rain expected to help ease the flash drought conditions that is
developing over much of the area. Have also adjusted max temps
down a bit...although SE OK/portions of E TX will remain in the
upper 90s for one more day and heat indices near 105 degrees. The
areas of convection should eventually spread into SE OK/E TX by
Monday as this weakness aloft moves into these areas. Have
increased pops to mid/high chance again Monday...with even cooler
temps expected areawide given the cloud cover/convection.
Should still see a weakness in the flow aloft in wake of this
departing disturbance as it drifts farther W into TX...resulting
in the continued chance for isolated to sct convection areawide
Tuesday and Wednesday. As was mentioned Friday morning...the upper
trough over the Wrn Atlantic E of the Fla coast should close off
tonight and drift W across the Fla peninsula Sunday...and across
the Gulf coast through midweek. The ECMWF is a bit faster in
bringing this opening inverted trough across the region
Tuesday...with the GFS still on track Wednesday which should help
enhance the weaknesses aloft to focus mainly diurnal convection
over the region. Afterwards...convection may be more isolated
before the approach of a weak trough aloft that is progged to
drift SE across OK/AR during the Friday/Saturday timeframe
affecting mainly the Nrn zones. Temps should also return to climo
by the mid to late week timeframe as well.
Thank you WFO/s JAN and LZK for collaboration this morning.
Prelims to follow below...
.PRELIMINARY POINT TEMPS/POPS...
SHV 99 79 95 76 / 30 20 40 30
MLU 97 75 93 75 / 30 30 50 30
DEQ 100 75 97 75 / 30 20 30 30
TXK 100 78 96 75 / 30 20 40 30
ELD 99 76 93 74 / 30 30 50 30
TYR 100 79 98 77 / 20 10 20 30
GGG 100 77 97 76 / 20 10 30 30
LFK 98 75 97 75 / 20 10 30 30
AR...Heat Advisory until 7 PM CDT this evening for ARZ050-051-059>061-
LA...Heat Advisory until 7 PM CDT this evening for LAZ001>006-010>014-
OK...Heat Advisory until 7 PM CDT this evening for OKZ077.
TX...Heat Advisory until 7 PM CDT this evening for TXZ096-097-108>112-