Area Forecast Discussion
Issued by NWS Tulsa, OK

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FXUS64 KTSA 171635
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
1135 AM CDT Tue Apr 17 2018

...UPDATE...

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.

VFR conditions will prevail through the period. Gusty winds will
also prevail, with south to southwest winds becoming northwesterly
08-12Z behind a cold front.

&&

.PREV DISCUSSION... /Issued 1020 AM CDT Tue Apr 17 2018/

..UPDATE...

DISCUSSION...
Fire weather is the dominant short term forecast concern, with
near Red Flag conditions now expected across a small part of
northeast Oklahoma. A Red Flag Warning has been issued for this
afternoon and into early evening for mainly western sections of
Osage and Pawnee counties. While it does not look like a slam dunk
that criteria - largely the minimum relative humidity criterion -
will be met, the persistent dry fuels tipped the scales despite
the marginal conditions. 12Z OUN sounding supports maximum
temperatures to the northwest of Tulsa between 85 and 90 degrees
today, and forecast highs have been adjusted a few degrees upward
as a result. These higher temperatures, in part, should lead to
minimum relative humidities nearing 25 percent in Osage and Pawnee
counties. Southerly winds will remain gusty areawide through the
afternoon and into the evening, with a shift to the southwest and
then the northwest as a cold front passes through the region
tonight. This wind shift will have an effect on any ongoing fire
fighting efforts and should be monitored closely.

PREV DISCUSSION... /Issued 613 AM CDT Tue Apr 17 2018/

AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Southerly sfc wind gusts 25-30kts by afternoon across all
sites, especially the NE OK sites. Dry cold front to move through
the area in the 08z-11z time period. SFC winds to become northwest
with gusts of 20-30kts to ensue behind the boundary.

PREV DISCUSSION... /Issued 332 AM CDT Tue Apr 17 2018/

DISCUSSION...

The main forecast concerns over the next 24 to 48 hours will be
winds and fire weather. Focus then turns to rain/storm chances
this weekend.

Current surface analysis shows a warm front stretching along or
just north of I-40 across western and central OK, then southeast
roughly along the Indian Nation Turnpike. South of the front,
dewpoints in the low 50s in south central OK. The front lifts
north into KS and MO by this afternoon in response to deepening
surface low pressure over western KS. All of this is occurring in
response to a progressive and rather strong shortwave trough
current moving across the Great Basin attm and headed for the
central Plains tonight. South to southwest winds increase today,
but the rising dewpoints should keep humidities high enough to
avoid the need for fire weather headlines. A much warmer day is in
store as the warm sector makes a return to our area, at least for
a day, with highs expected to top out in the upper 70s to mid
80s. Today will be the warmest day of this forecast.

A cold front will sweep southeast over our region as the surface
low moves east across KS and MO tonight into Wednesday morning in
association with the upper trough. Locations ahead of the front
should stay mild tonight as winds stay fairly breezy. Behind the
front on Wednesday, a deep mixing/momentum transfer regime will
lead to strong gusty winds across northern OK. The dry and windy
conditions will approach critical fire weather levels across
portions of NE OK mainly along and west of highway 75. No
headlines will be issued at this time, however, this will be
reevaluated later today.

Models remain consistent in bringing widespread rain to the region
this weekend with the next upper level storm system. They are also
consistent in suggesting that the warm sector will stay just to
our south, with the surface low tracking across north TX and into
the ArkLaTex. Thus, while there will certainly be potential for
elevated storms, especially across southern OK and west central
AR, severe weather potential looks pretty low at this point. It is
worth noting that the state of Oklahoma has not had a tornado so
far in 2018. The record for the latest start to tornado season is
April 26th, 1962. Based on the latest data, the upper/surface
pattern will tend to favor cooler weather and not severe weather.
Therefore, we may break the record for the latest start to the
tornado season in Oklahoma. I`m not complaining.

Lacy

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Red Flag Warning until 9 PM CDT this evening for OKZ054-059.

AR...None.
&&

$$


AVIATION.....22


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