Flash Flood Warning 8, NWS Shreveport, LA

214 
WGUS74 KSHV 201410
FFSSHV

Flash Flood Statement
National Weather Service Shreveport LA
910 AM CDT SAT MAY 20 2017

TXC073-201515-
/O.CON.KSHV.FF.W.0008.000000T0000Z-170520T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cherokee TX-
910 AM CDT SAT MAY 20 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 AM CDT FOR
CHEROKEE COUNTY...

At 907 AM CDT, local law enforcement reported heavy rain due to a 
thunderstorm over much of Cherokee County. Up to three inches of 
rain have already fallen. Law enforcement officials have already 
reported a few road closures due to flooding.

Some locations that will experience flooding include...
Jacksonville, Rusk, Alto, Mount Selman, Ponta, Mixon, Reese,
Maydelle, New Summerfield, Gallatin, Reklaw, Cuney, Teaselville and
Concord.

The heaviest rain has moved east of the area. Flooding is still 
ongoing, but this should allow any high waters to slowly recede.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 3213 9499 3169 9499 3157 9520 3158 9526
      3159 9528 3161 9526 3163 9529 3168 9529
      3172 9534 3174 9533 3173 9537 3175 9536
      3176 9540 3182 9540 3185 9544 3193 9542
      3196 9545 3199 9545 3205 9542 3213 9546

$$

09

Area Forecast Discussion
National Weather Service Shreveport LA
552 AM CDT Sat May 20 2017

.AVIATION...
Line of shra and tsra has moved across KTYR and KGG terminals, and
movg into KTXK terminal. KSHV and KLFK may see this convection
hold together by 20/12-14z. Vrbl mostly mvfr cigs exist to both
the east and west of this convection, as does lgt s-se winds.
Brief w-nw wind gusts possible along leading edge of convection.
Mostly low vfr cigs before 20/18z. Isold to sct convection may
redevelop later this aftn and tonight invok cold front slowly movg
across area overnight. This front may stall out and affect mainly
KLFK and KMLU beyond end of 21/12z fcst cycle with additional low
cigs and precip possible./07/.

&&

.PREV DISCUSSION... /issued 338 AM CDT Sat May 20 2017/

DISCUSSION...
Regional Radar Mosaic showing a decaying line of showers and
thunderstorms extending from Southeast Oklahoma into portions of
North Central and Central Texas. While the coverage of the
activity has held its own over the last couple hours, intensity is
beginning to wane as expected. This is the case even with
mesoscale analysis showing surface based CAPE values near 2K J/KG
just ahead of the convection across portions of Southeast Oklahoma
and Southwest Arkansas. Low level jet of 30-40kts is trying to
sustain the convection but it's slowly beginning to veer around
to more of a southwesterly direction thus becoming more parallel
to the convection which could be counteracting the increased
instability downstream. Also starting to see some CINH downstream
from the line of convection as well which may suggest that the
line may be trying to become slightly elevated as it begins moving
into our region.

Models continue to struggle with the timing of the remnants of
this convection moving into our region, especially the 00/06z NAM
output which has been playing catchup all night and for that
reason has been discounted for this short term forecast cycle. The
00z GFS may be a little too aggressive moving the activity into
our NW zones, at least early this morning, but will be used along
with a blend of 00z ECMWF through the short term portion of the
forecast. All this to say the line of convection should continue
to decay as it moves into our region this morning but with PWATS
forecast to exceed 1.5 inches across a good portion of our region
today, week divergence aloft and weak frontal forcing from the
northwest not to mention a mid level shear axis present in
southwest flow aloft in advance of a deep shortwave trough across
the Central/Southern Plains, confidence is high that convection
should redevelop with the aid of daytime heating across most of
the Four State Region today. All models support increased coverage
throughout the day and for that reason, have kept high chance to
likely pops going for the daytime hours. SPC has included much of
the eastern half of our region including most of Northern
Louisiana and Southern Arkansas in a Slight Risk of Severe
Thunderstorms this afternoon/evening. This risk is highly
conditional on enough surface based instability developing ahead
of a cold front this afternoon as upper forcing will be weak as
will low level and deep level shear. Having said this, multicell
thunderstorms appear to be the best bet with an isolated hail
and/or wind damage threat. The cold front was located well behind
the convection early this morning and will not be moving into our
far northwest zones until near 18z today, and will make slow
southeast progress through 00z, pushing into Northwest Louisiana
beyond 00z this evening. Kept pops in the likely category across
our southeast zones overnight as this will be the last area worked
on by the front.

West southwest flow aloft will contain weak perturbations in this
flow which could generate isolated to scattered convection on
Sunday even with the post frontal conditions across our region.
Best coverage would likely be south of the I-20 corridor through
Sunday Night before we begin to see changes again in the upper
level pattern to our north and west.

Vigorous upper level trough will remain locked across the Northern
Plains/Upper Great Lakes region of the country with rather quick
westerly flow across the Southern Plains to begin the upcoming
work week. A disturbance caught in this flow across the TX Hill
Country will quickly eject out our way with increasing chances of
showers and thunderstorms to our west as we go through the day
Monday. This is the lead disturbance in advance of a developing
longwave trough across the Northern and Central Plains that will
eventually become our permanent weather maker Monday Night into
Tuesday with increasing chances of thunderstorms. This longwave
trough should eventually become cutoff from the westerlies across
the Tenn Valley on Wed as strong cold air advection sweeps into
our region from the northwest in the wake of a cold front which
should have swept through our entire region Tue Night. Post
frontal showers will be possible across our eastern half on Wed
due to the proximity of the closed low to our region before we see
an end to the precip and clearing skies from west to east Wed
Night into Thu. This cooler air will begin to moderate as we move
into the later half of the upcoming work week but the forecast
should remain dry through this period as well.

Prelims to follow...13.

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  84  67  81  63 /  70  50  30  10
MLU  86  68  81  63 /  60  60  40  10
DEQ  79  56  81  54 /  70  20  10  10
TXK  81  61  80  59 /  70  30  10  10
ELD  82  63  79  57 /  70  50  30  10
TYR  82  63  81  63 /  70  40  30  20
GGG  82  64  81  62 /  70  50  30  10
LFK  85  69  84  67 /  70  50  50  20

&&

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

Hazardous Weather Outlook
National Weather Service Shreveport LA
409 AM CDT Sat May 20 2017

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-
TXZ096-097-108>112-124>126-136>138-149>153-165>167-201800-
Sevier-Howard-Little River-Hempstead-Nevada-Miller-Lafayette-
Columbia-Union-Caddo-Bossier-Webster-Claiborne-Lincoln-De Soto-
Red River-Bienville-Jackson-Ouachita-Sabine-Natchitoches-Winn-
Grant-Caldwell-La Salle-McCurtain-Bowie-Franklin-Titus-Camp-
Morris-Cass-Wood-Upshur-Marion-Smith-Gregg-Harrison-Cherokee-Rusk-
Panola-Nacogdoches-Shelby-Angelina-San Augustine-
409 AM CDT Sat May 20 2017

This Hazardous Weather Outlook is for portions of south central
Arkansas, southwest Arkansas, north central Louisiana, northwest
Louisiana, southeast Oklahoma, east Texas and northeast Texas.

.DAY ONE...Today and Tonight...

Showers and thunderstorms will increase across the Four State
Region as we go through the day into this evening. With the aid of
daytime heating, some of these storms could become strong to
severe with damaging wind gusts and the possibility of large hail
the main threats. Also locally heavy downpours will be possible
this morning across the Middle Red River Valley of Northeast
Texas, Southeast Oklahoma and Southwest Arkansas. The activity
should begin diminishing in coverage and intensity later this
evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday...

Showers and thunderstorms will continue to be in the forecast
through at least Tuesday of the upcoming work week. A strong cold
front will move through the entire Four State Region Tuesday Night
into early Wednesday bringing an end to the wet weather pattern.
Much cooler temperatures will be in the forecast for the middle
and later half of the work week.

.SPOTTER INFORMATION STATEMENT...

Activation of emergency management personnel...amateur radio
operators...and storm spotters may be needed later today into
the evening hours due to the possibility of severe thunderstorms.

13