Winter Storm Warning 1, NWS Amarillo, TX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
639 AM CDT THU MAR 26 2009

.AVIATION...
FOR THE 12Z TAFS...VFR CONDITIONS SHOULD PERSIST THROUGH THE FIRST 6
HOURS...AFTER THAT CONDITIONS WILL BEGIN TO DETERIORATE. THE COLD
FRONT IS EXPECTED TO PUSH THROUGH THE REGION BETWEEN 21 AND
01Z...RESULTING IN A QUICK SHIFT TO STRONG NORTHERLY WINDS.
PRECIPITATION WILL START IN THE NORTHWESTERN AREAS...INCLUDING KGUY
AND KDHT...THIS AFTERNOON AS RA OR SHRA...SWITCHING OVER TO RASN
BRIEFLY...BEFORE SWITCHING OVER TO SN FOR THE REMAINDER OF THE TAF
PERIOD. WHEN THE SWITCH OVER TO SN OCCURS...EXPECT IFR CONDITIONS OR
LOWER...AS IN ADDITION TO THE SN...BLSN IS ALSO A POSSIBILITY. MORE
SPECIFIC INFORMATION ON TIMING WILL BE AVAILABLE WITH THE 18Z TAFS.

SJOHNSON
&&

.PREV DISCUSSION... /ISSUED 406 AM CDT THU MAR 26 2009/

DISCUSSION...
BIGGEST CONCERNS CONTINUE TO BE THE UPCOMING WINTER STORM SYSTEM
WHICH WILL AFFECT THE PANHANDLES TONIGHT THROUGH FRIDAY NIGHT.
CONCERNS THIS PACKAGE IS BLIZZARD CONDITIONS POSSIBLE OR WINTER STORM
WARNING CRITERIA. UNCERTAINTY AND LOW CONFIDENCE IN WHICH CONDITIONS
BEING MET RESULTS IN RELUCTANCE TO UPGRADE TO EITHER A BLIZZARD
WARNING WESTERN HALF OR WINTER STORM WARNING ALL SECTIONS OR EASTERN
HALF. DECIDED TO LET THE DAY SHIFT TAKE CLOSER LOOK AND UPGRADE TO
APPROPRIATE WARNING AS NEEDED. MADE VERY LITTLE CHANGES TO PREVIOUS
GRIDS AND FORECAST. TIMING OF WINTER STORM APPEARS TO BE FROM TONIGHT
THROUGH FRIDAY NIGHT...HOWEVER NAM SLOWER IN MOVING THE UPPER LOW
EASTWARD INTO OK UNTIL SATURDAY. GFS SLIGHTLY FASTER IN EJECTING THE
UPPER LOW INTO OK BY 12Z SATURDAY. TIMING OF PRECIP ENDING DEPENDS ON
WHICH SOLUTION CORRECT. THEREFORE...DECIDED TO MAINTAIN POPS IN THE
EASTERN SECTIONS OF THE PANHANDLES BETWEEN 12Z AND 18Z SATURDAY.
LATER SHIFTS CAN END PRECIP EARLIER IF NECESSARY. UNDERCUT MOS
GUIDANCE FOR MAX TEMPS OVER THE WEEKEND DUE TO EXPECTED SNOW COVER
LINGERING.

COLD FRONT FORECAST TO BACKDOOR THE PANHANDLES THIS AFTERNOON AND
PUSHING THROUGH THE AMARILLO AREA AND SOUTHWESTERN TX PANHANDLE BY
00Z FRIDAY OR SO. AHEAD OF THE COLD FRONT THIS AFTERNOON...MAINLY
ACROSS THE SOUTH CENTRAL AND SOUTHWEST TX PANHANDLE...DOWNSLOPING
WESTERLY WINDS WILL INCREASE INTO BREEZY OR POSSIBLY WINDY CATEGORY.
DRIER AIR WITH THE DOWNSLOPING WINDS WILL ALLOW RH VALUES TO DROP.
BEHIND THE FRONT...WINDS WILL SHIFT TO THE NORTHEAST AND INCREASE
INTO WINDY CATEGORY. LOW LEVEL MOISTURE POOLING BEHIND THE FRONT WITH
GOOD ISENTROPIC LIFT WILL RESULT IN LOW CLOUDS DEVELOPING ALONG WITH
POSSIBLE PRECIP BY LATE TODAY. RECONFIGURED POPS THIS AFTERNOON TO
THE OK AND EXTREME NORTHERN TX PANHANDLES. SUBSIDENCE BEHIND
DEPARTING UPPER LOW SATURDAY AND NORTHWESTERLY FLOW ALOFT WILL ALLOW
FOR DRIER CONDITIONS BY SATURDAY AFTERNOON AND SATURDAY NIGHT. ZONAL
FLOW ALOFT SUNDAY WILL TRANSITION TO SOUTHWESTERLY BY SUNDAY NIGHT AS
ANOTHER CLOSED UPPER LOW TRACKS EASTWARD OUT OF THE CENTRAL ROCKIES
INTO THE CENTRAL PLAINS STATES. EXPECT PANHANDLES TO BE DRY-SLOTTED
BY THIS SYSTEM AS MAIN UPPER LEVEL DYNAMICS REMAIN NORTH OF THE
FORECAST AREA. SURFACE LOW SUNDAY OVER EASTERN CO WITH PACIFIC COLD
FRONT SOUTHWEST OF THE LOW WILL TRACK EAST AND THE COLD FRONT WILL
MOVE THROUGH THE PANHANDLES SUNDAY NIGHT. SLIGHTLY COOLER CONDITIONS
MONDAY AND CONTINUED DRY. NEXT CHANCE FOR PRECIP EXPECTED LATE NEXT
WEEK AS STRONG COLD FRONT PUSHES SOUTH THROUGH THE PANHANDLES LATE
WEDNESDAY INTO WEDNESDAY EVENING. CLOSED UPPER LOW OVER THE GREAT
BASIN REGION EXPECTED TO DIG SOUTH INTO THE SOUTHWESTERN STATES/FOUR
CORNERS REGION LATE WEDNESDAY INTO EARLY THURSDAY...AND THEN
APPROACHING THE PANHANDLES FROM THE SOUTHERN ROCKIES BY LATE
THURSDAY. CONTINUED WITH LOW END SLIGHT CHANCE POPS WEDNESDAY NIGHT
AND THURSDAY.

SCHNEIDER

FIRE WEATHER...
APPEARS ONE MORE DAY OF POSSIBLE CRITICAL FIRE WEATHER CONDITIONS
THIS AFTERNOON BEFORE A STRONG COLD FRONT MOVES THROUGH BY EARLY THIS
EVENING. THE SOUTHWEST AND SOUTH CENTRAL TX PANHANDLE HAVE THE BEST
CHANCE OF EXPERIENCING RED FLAG CONDITIONS THIS AFTERNOON AS
DOWNSLOPING WESTERLY WINDS INCREASE TO AROUND 15 TO 25 KNOTS WITH
HIGHER GUSTS AND RH VALUES BETWEEN 10 AND 15 PERCENT. TIME FOR RED
FLAG CONDITIONS WILL BE EARLY...BETWEEN 18Z AND 22Z THURSDAY...AS
COLD FRONT TO QUICKLY PUSH FROM NORTHEAST TO SOUTHWEST ACROSS THE
AREA BY 00Z FRIDAY SHIFTING THE WINDS TO THE NORTHEAST 20 TO 30 KNOTS
WITH HIGHER GUSTS AND RH VALUES RISING QUICKLY TO ABOVE 25 PERCENT
FOLLOWING THE PASSAGE OF THE FRONT. FIRE WEATHER CONCERNS WILL BE LOW
TO NONE FRIDAY THROUGH THE WEEKEND AS A WINTER STORM SYSTEM
APPROACHES AS EARLY AS TONIGHT. AFTER TODAY...DO NOT SEE ANY FIRE
WEATHER CONCERNS THROUGH NEXT WEEK.

SCHNEIDER

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY MORNING
     FOR THE FOLLOWING ZONES: COLLINGSWORTH...DONLEY...GRAY...
     HEMPHILL...LIPSCOMB...OCHILTREE...ROBERTS...WHEELER.

     BLIZZARD WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR
     THE FOLLOWING ZONES: ARMSTRONG...CARSON...DALLAM...DEAF
     SMITH...HANSFORD...HARTLEY...HUTCHINSON...MOORE...OLDHAM...
     POTTER...RANDALL...SHERMAN.

     RED FLAG WARNING FROM NOON TODAY TO 6 PM CDT THIS EVENING FOR
     THE FOLLOWING ZONES: ARMSTRONG...CARSON...DEAF SMITH...
     OLDHAM...POTTER...RANDALL.

OK...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY MORNING
     FOR THE FOLLOWING ZONES: BEAVER.

     BLIZZARD WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR
     THE FOLLOWING ZONES: CIMARRON...TEXAS.

&&

16/11

TEXAS/OKLAHOMA PANHANDLES HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AMARILLO TX
602 AM CDT THU MAR 26 2009

OKZ001>003-TXZ001>020-261800-
ARMSTRONG-BEAVER-CARSON-CIMARRON-COLLINGSWORTH-DALLAM-DEAF SMITH-
DONLEY-GRAY-HANSFORD-HARTLEY-HEMPHILL-HUTCHINSON-LIPSCOMB-MOORE-
OCHILTREE-OLDHAM-POTTER-RANDALL-ROBERTS-SHERMAN-TEXAS-WHEELER-
602 AM CDT THU MAR 26 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE TEXAS AND OKLAHOMA
PANHANDLES.

.DAY ONE...

WINDS OF 15 TO 25 MPH ARE EXPECTED TODAY...INCREASING TO 25 TO 35
MPH THIS EVENING. THEREFORE...CAUTION IS ADVISED ON ALL AREA LAKES.

IN ADDITION TO THE STRONG WINDS...DRY CONDITIONS...WITH RELATIVE
HUMIDITY VALUES BELOW 15 PERCENT...ARE EXPECTED TO DEVELOP IN THE
SOUTHEASTERN AND SOUTHCENTRAL TEXAS PANHANDLE. THEREFORE A RED FLAG
WARNING IS IN EFFECT TODAY FOR THOSE LOCATIONS.

A BLIZZARD WATCH IS IN EFFECT OVER THE WESTERN AND CENTRAL
PARTS OF THE TEXAS AND OKLAHOMA PANHANDLES BEGINNING TONIGHT. A
WINTER STORM WATCH IS IN EFFECT FOR THE EASTERN PARTS OF THE
TEXAS AND OKLAHOMA PANHANDLES BEGINNING TONIGHT. RAIN THAT WILL
SPREAD OVER THE REGION TODAY THROUGH THIS EVENING WILL CHANGE TO A
RAIN AND SNOW MIX...BEFORE CHANGING TO ALL SNOW LATE TONIGHT. IN
ADDITION STRONG NORTHERLY WINDS WILL CREATE AREAS OF BLOWING SNOW.

.DAYS TWO THROUGH SEVEN...

A BLIZZARD WATCH AND WINTER STORM WATCH CONTINUES THROUGH SATURDAY
MORNING. SNOW...HEAVY AT TIMES...AND STRONG WINDS RESULTING IN
WIDESPREAD BLOWING SNOW...WILL CONTINUE FRIDAY AND FRIDAY NIGHT.
SNOW ACCUMULATIONS ACROSS THE REGION ARE EXPECTED TO RANGE FROM 4
INCHES IN THE SOUTHERN TEXAS PANHANDLE TO OVER A FOOT IN THE
OKLAHOMA PANHANDLE. THE SNOW IS EXPECTED TO END SATURDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT SNOW AMOUNTS AND AREAS OF BLOWING
SNOW.

SJOHNSON