575 
FXUS64 KTSA 012228
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
528 PM CDT Tue May 1 2018

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
MVFR ceilings will develop at all sites late tonight and persist
for much of the rest of the forecast period. Some improvement to
VFR may occur at KFSM Wednesday afternoon. LLWS will continue to
be mentioned at KFSM overnight into Wednesday morning. Southerly
winds will gust to over 25 knots at times, especially during the
day Wednesday.

&&

.PREV DISCUSSION... /Issued 320 PM CDT Tue May 1 2018/ 

DISCUSSION...

Severe weather potential thru Thursday is the main forecast
concern. After an unusually cool April, finally some spring-like
weather as May arrives. Southwest flow prevails over the Plains
downstream from a strong upper trough over southern CA. At the
surface, a nearly stationary frontal boundary extends from a low
pressure over the Great Lakes down to western Kansas. A dryline
extends south down into the eastern OK/TX Panhandles.

While the bulk of the storm coverage will be from the triple point
and then northeast along the frontal zone, trends in the hi-res 
data suggest isolated storm development potential on the dryline 
down into western OK as well. However, storms will likely not
survive too far off of the dryline due to a strong capping
inversion across OK. Thus, the storm/severe weather threat for
this afternoon and tonight too low to mention in the forecast.

Model data indicates that a subtle wave rotating around the base
of the parent southwest CONUS trough will lift northeast into the
region and will be timed favorably for the diurnal heating cycle.
The hi-res ARW, ECMWF and to some degree the GFS develop 
convection across southern KS and northwest OK warm sector
Wednesday afternoon. This convection is expected to progress
across southeast KS and northeast OK during the evening hours, due
to the weakening cap. Forecast soundings over the region show 
sharply curved cyclonic hodographs in the low levels and large
CAPE. Since the initiation zone will be some distance away from 
us, convective mode will be important in determining the type of 
severe weather. If any discrete storms make it this far east, a 
strong tornado and very large hail is possible. If storms congeal 
into bows, given the strong low level shear, some QLCS tornadoes 
and some large hail will be possible. The threat will be more 
isolated farther south down into southeast OK.

Another round of storms is expected to get going late Wednesday
night across west TX with the ejection of the main upper trough
into the Plains, and this activity is expected to lift northeast 
up into the region Thursday morning. This morning convection could
affect the warm sector quality over our region going into the
afternoon and thus the severe forecast is a bit more uncertain 
for Thursday. The synoptic front then pushes south across the 
region Thursday night, with some storm potential in association 
with the boundary indicated in the data. The weather should clear 
out of our area during the day Friday with the southward moving 
front, and it looks like pleasant tranquil weather again for the 
second straight weekend. 

Lacy

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.

&&

$$

AVIATION.....05