Frost Advisory 1, NWS Amarillo, TX

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
1255 PM CDT Sun Apr 15 2018

.AVIATION...
For the 18Z TAFs, south winds will increase and become gusty by
mid to late Monday morning as low pressure forms over eastern
Colorado and eastern New Mexico. Some high level clouds are also
expected through this fcst period. Overall, VFR conditions will
prevail at KAMA, KDHT, and KGUY through 18Z Monday.

Andrade

&&

.PREV DISCUSSION... /Issued 606 AM CDT Sun Apr 15 2018/

AVIATION...
For the 12z TAFs...
VFR forecast for next 24 hours.  No appreciable changes from
forecast of six hours ago.  Good flying weather on tap for the
next 24 hours.  Light northwest surface winds will diminish
further by late afternoon, and will trend to southeast tonight.
No clouds expected today, with high clouds moving in this evening.

Cockrell

PREV DISCUSSION... /Issued 525 AM CDT Sun Apr 15 2018/

DISCUSSION...
Latest upper level analysis reveals departing closed low entering
the Ohio Valley region with northwest flow trailing behind.
Heights have been increasing and should continue to do so as a
weak ridge traverses the Plains today through Monday. At the
surface, winds are light out of the northwest and temperatures
are below freezing across most of the Panhandles. The Hard Freeze
Warning will stay in affect until 9 AM for all of the TX/OK
Panhandles. Temperatures are expected to warm into the 60s and
even a few 70s this afternoon. Winds in the eastern Panhandles may
become breezy later this morning, but should become light this
afternoon and evening as the backside jet streak of a 700mb low
continues to shift away from the Panhandles. Overall, today should
be very pleasant. For tonight, temperatures should remain above
freezing for most locations. The one exception may be the eastern
Oklahoma Panhandle where temperatures may dip just below freezing.
Held off on any freeze products due to the small area and overall
uncertainty.

The weak upper level ridge axis traverses the Panhandles on
Monday afternoon as the next more progressive upper shortwave
moves down out of the Pac NW. A lee trough is expected to develop
during the afternoon Monday, and will contribute to breezy
southwest winds across the area as the surface pressure gradient
increases. A notable 850mb thermal ridge is also progged to expand
over West Texas Monday afternoon and should have no problem
mixing to the surface. Thus, expect high temperatures around 10-15
degrees above average.

On Tuesday, the upper ridge breaks down as the shortwave and
attendant 700-500 mb jet streaks nose over the Panhandles.
Current guidance suggest 40-50 knot winds at 700mb and 60-75 knot
winds at 500mb overspreading the Panhandles with the strongest
part of the mid level jet streak over the northwestern zones by
Tuesday afternoon. Any high level cirrus early Tuesday should
decrease, and ample mixing is expected to take place. Moreover,
strong downslope winds are expected as momentum transfer increases
in the afternoon. Wind highlights may be needed, especially for
the northwestern zones. In addition, low level cyclogenesis is
expected to commence in eastern CO as the shortwave crosses the
Rockies. This feature will initially help expand an 850mb thermal
ridge over a good portion of the southern plains, bringing another
day of very warm temperatures. the Deterministic guidance quickly
ejects the surface low east-northeast with an attendant Pacific
Front in its wake. This front will shift winds to the west-
northwest Tuesday evening becoming north overnight. Winds will
gradually diminish Wednesday morning as cooler air filters in.
Temperatures on Wednesday and Thursday should be closer to
average.

Another transient upper ridge shifts across the area Wednesday
with an upper trough digging into the Four Corners region
Thursday into Friday. Long range probabilistic and deterministic
guidance continues to advance this wave such that moisture is able
to feed into the Panhandles. Positive theta-E advection takes
place on backed low level wind fields beginning as early as
Thursday afternoon. Moreover, thunderstorms are in the forecast
Thursday through Friday. There are some notable difference in the
long range guidance with the GFS being far more progressive with
the system, ending precip chances earlier compared to the ECMWF.

Ward

FIRE WEATHER...
A brief window of elevated fire weather can't completely be ruled
out today in the eastern Panhandles. Northwest winds may touch 15
mph late this morning as RH values approach 20 percent. However,
winds are expected to decrease going into the afternoon.

Elevated to critical fire weather conditions are expected Monday
afternoon. A lee trough and 850 mb thermal ridge will contribute
to southwest winds of 15-25 mph and min RH values around 6-8
percent as temperatures rise into the 80s. A Fire Weather Watch
has been issued for the western Panhandles where confidence is
higher that the required duration of critical conditions will be
achieved. The eastern Panhandles should see solid elevated /
spotty critical Fire Weather conditions with winds being the
limiting factor. RH recovery will be limited Monday night.

Widespread critical Fire Weather conditions are expected across
the Panhandles Tuesday afternoon and evening as a strong mid-
level jet streak overspreads an 850mb thermal ridge. A Fire
Weather Watch has been issued for late Tuesday morning through
late Tuesday evening. Extremely critical fire weather conditions
are possible mainly in the western half of the combined Panhandles
due to very strong downslope winds with gusts up to 50-55 mph
possible. Min RH values should easily dive into the single digits
across all of the Panhandles with temperatures again in the 80s. A
Pacific cold front will shift winds to the west-northwest Tuesday
evening, becoming north overnight.

Ward

&&

.AMA Watches/Warnings/Advisories...
TX...Fire Weather Watch from Tuesday morning through Tuesday evening
     for the following zones: Armstrong...Carson...
     Collingsworth...Dallam...Deaf Smith...Donley...Gray...
     Hansford...Hartley...Hemphill...Hutchinson...Lipscomb...
     Moore...Ochiltree...Oldham...Potter...Randall...Roberts...
     Sherman...Wheeler.

     Fire Weather Watch from Monday afternoon through Monday evening
     for the following zones: Armstrong...Carson...Dallam...Deaf
     Smith...Hartley...Moore...Oldham...Potter...Randall...
     Sherman.

OK...Fire Weather Watch from Tuesday morning through Tuesday evening
     for the following zones: Beaver...Cimarron...Texas.

     Fire Weather Watch from Monday afternoon through Monday evening
     for the following zones: Cimarron.

&&

Hazardous Weather Outlook
National Weather Service Amarillo TX
539 AM CDT Sun Apr 15 2018

OKZ001>003-TXZ001>020-152200-
Cimarron-Texas-Beaver-Dallam-Sherman-Hansford-Ochiltree-Lipscomb-
Hartley-Moore-Hutchinson-Roberts-Hemphill-Oldham-Potter-Carson-
Gray-Wheeler-Deaf Smith-Randall-Armstrong-Donley-Collingsworth-
539 AM CDT Sun Apr 15 2018

This Hazardous Weather Outlook is for the Texas and Oklahoma
Panhandles.

.DAY ONE...Today and Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Elevated to critical fire weather conditions are expected to
return on Monday afternoon. Widespread critical fire weather
conditions with areas of extremely critical fire weather
conditions are expected across the Panhandles Tuesday.

Isolated thunderstorms are possible Thursday afternoon in the
western Panhandles and area wide on Friday. A strong thunderstorm
can't be ruled out.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated at this time.

Area fire managers and emergency officials should be alert for
elevated to critical fire weather conditions Monday and Tuesday.

Ward