Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 231705 AAA
AFDOUN

Area Forecast Discussion...UPDATED
National Weather Service Norman OK
1205 PM CDT MON MAY 23 2016

.AVIATION...23/18Z TAF ISSUANCE...
Tricky aviation forecast over the next several hours. Broken to
overcast MVFR ceilings will continue to impact airfields and TAF
sites across portions of central and southern Oklahoma through the
mid to late afternoon. Across western Oklahoma and western north
Texas, scattered to broken MVFR ceilings will continue to improve
to VFR through the afternoon. The biggest concern for aviation
will be thunderstorm development late this afternoon and evening
across portions of western Oklahoma and western north Texas.
Confidence in timing and coverage has increased for TAF sites
across the southwest, including KCSM/KHBR/KLAW/KSPS. Therefore,
utilized TEMPO groups, after 00Z for most. Expect a complex of
storms to develop similar to last night, primarily impacting
southern Oklahoma and northern Texas overnight.

Kurtz

&&

.PREV DISCUSSION... /issued 928 AM CDT MON MAY 23 2016/

UPDATE...
Quick morning update to thunderstorm chances through this
evening.

DISCUSSION...
Jumping on the forecast early this morning given the chance for
severe storms developing on/just east of the Caprock and moving
into far western north Texas and southwestern Oklahoma late this
Afternoon and evening. Guidance, both traditional and mesoscale,
are in decent agreement with the redevelopment of the dryline on
the Llano Estacado and its mixing eastward through the mid
afternoon across the Texas and Oklahoma Panhandles. Dew points
across the Panhandles to central Oklahoma continue to reside in
the low to mid 60s, with sites farther south in western north
Texas already reaching the upper 60s to near 70s. the MCS that
moved across southern Oklahoma and northern Texas overnight has
had some impact, but recovery is already well underway farther
west. The fly in the ointment at the moment is the broken to
overcast stratus spread across the area. In western Oklahoma,
breaks have been fairly evident, and temperatures are already in
the upper 60s and lower 70s. Agree with the night shift and with
latest SPC outlook, some form of a triple point will develop
south/southwest of the Red River, east of the Caprock this
afternoon. Solutions from the HRRRx and TTU WRF continue to pick
this as the primary initiation point. The operational HRRR and
traditional guidance continue to fire convection along a surging
point in the dryline early this afternoon in northwestern
Oklahoma/southwestern Kansas. This is likely overdone given the
current conditions, overcast skies, limiting heating this morning.
However, isolated thunderstorms may develop in the region, but
probably not as widespread as some of the solutions attempt.

Therefore, increased precip chances to likelys across southern
Oklahoma and western north Texas from late this afternoon through
the evening and into the overnight hours. Confidence is high for
storm development and and increase from chance PoPs was necessary.
Not to rehash the previous discussion, but instability and shear
will be plenty enough for the development of large damaging hail,
damaging winds, and the possibility of a few tornadoes.

Of greater concern for many will be the potential for flooding
overnight, especially across portions of southern Oklahoma and
northern Texas where excessive rainfall fell last night and this
morning. Once again, this afternoon`s storms are expected to merge
into a complex and propagate eastward overnight, slowly. A flood
watch is in effect for this region and may need to be extended,
but this will be addressed with the afternoon forecast.

Kurtz

PREV DISCUSSION... /issued 850 AM CDT MON MAY 23 2016/

UPDATE...
Updated pops and slowed diurnal warming trend this morning.

DISCUSSION...
Showers/storms continue to move east with a new area of storms
that developed just east of OKC/Norman. Have updated short-term
pops with the latest trends in radar and satellite. HRRR/RAP and
various hi-res models show redevelopment before 18z across
northwest and central Oklahoma so have adjusted late morning pops
to account for this possibility. And made significant changes to
the hourly temperatures and dewpoints given the cloud cover will
keep temperatures cooler this morning and the post-convective
worked over airmass keeping dewpoints lower. Still expect we will
see eventual recovery to forecast highs, but it will likely take
some time.

PREV DISCUSSION... /issued 659 AM CDT MON MAY 23 2016/

DISCUSSION...
Please see the 12Z aviation discussion below.

AVIATION...
A few thunderstorms remain near SPS and OKC/OUN early this
morning, and may continue for a couple more hours. Otherwise,
expect MVFR cigs to return late this morning for a few terminals
before becoming VFR by this afternoon. Showers and thunderstorms
are expected again tonight, mainly after 00Z. Confidence in timing
is not exceptional, however, so expect some amendments/changes to
future TAFS.

PREV DISCUSSION... /issued 405 AM CDT MON MAY 23 2016/

DISCUSSION...
An MCS continues its track across southern OK and north TX early
this morning. Very heavy rainfall and damaging winds accompanied
it earlier, and are still expected across southern OK through the
early morning hours. Most of this activity should move out of our
area near or before sunrise. Later this afternoon storms will
initiate along the dryline again from the southeastern TX
panhandle into western and northwestern OK, and move east during
the evening hours. Supercells will be likely, with ALL severe
weather threats possible. The highest rainfall totals are again
expected over western and southwestern OK, and western north TX.
These areas already received a significant amount of rainfall this
morning so we have decided to issue a Flood Watch thru early Wed
AM.

The overall forecast has changed very little for the work week.
The severe threat will continue to shift slowly east each day
with the dryline and approaching upper trough. The tornado threat
should also increase during the late afternoon and early evening
hours with the onset of the LLJ, especially across western and
southwestern OK by Tue. There may be a break in COVERAGE Wednesday with
surface convergence becoming a bit more diffuse along the
dryline. However, if any isolated supercells can manage to develop
they will again be capable of producing ALL severe weather
threats.

By Thursday, a southern stream mid to upper level shortwave trough
is expected to lift over northeast TX and into SE OK around mid
day. Heavy rainfall and embedded supercells will be possible with
this activity. Further west, the upper trough will begin to near
the southern plains with rapid height falls and increasing mid to
upper flow expected over the dryline across western OK.
Widespread severe weather continues to appear possible thru
Thursday night, including the threat of tornadoes. Finally, by
Friday, the upper trough will being to lift northeastward but will
not pass overhead until late Friday night. Additional severe
weather will remain possible from along/just west of I35 through
eastern OK.

Additional storm chances are expected through the weekend and into
early next week as another upper trough moves over the western
CONUS and WSW flow aloft ahead of it continues over the Southern
Plains.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  67  83  68  86 /  50  20  50  20
Hobart OK         68  87  69  90 /  60  50  40  20
Wichita Falls TX  69  87  71  90 /  70  30  30  20
Gage OK           67  91  64  93 /  40  20  30  10
Ponca City OK     68  83  69  88 /  40  30  50  20
Durant OK         70  83  70  84 /  50  30  40  20

&&

.OUN Watches/Warnings/Advisories...
OK...Flood Watch from 3 PM CDT this afternoon through Wednesday
     morning for OKZ021>023-027-033>039-044-045.

TX...Flood Watch from 3 PM CDT this afternoon through Wednesday
     morning for TXZ083>090.

&&

$$

09/04/04



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