Severe Thunderstorm Warning 173, NWS Amarillo, TX

TEXAS/OKLAHOMA PANHANDLES FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AMARILLO TX
241 PM CDT SUN SEP 2 2001

A RATHER FAST BAND OF WESTERLIES CONTINUES ACROSS THE U.S./CANADIAN
BORDER WHILE THE REMAINDER OF THE COUNTRY REMAINS IN A WEAK
WESTERLY FLOW. THE EXCEPTION BEING ACROSS THE DESERT SOUTHWEST AND
INTO THE PANHANDLES WHERE 12Z RAOBS SHOWING WESTERLY 50KT WINDS AT
250MB. LATEST SURFACE ANALYSIS SHOWS A TROUGH ALONG THE CO/KS STATE
LINE STRETCHING SOUTHWEST INTO THE EASTERN NM PLAINS. DRIER AIR
WAS FILTERING INTO THE FAR NORTHWEST CWA WITH OK MESONET SHOWING 19Z
DEW POINTS OF 41F AT BOISE CITY AND KENTON. WE WILL HAVE TO KEEP
AN EYE ON ANY STORMS THAT DEVELOP IN THE NORTHWEST WITH LARGE
SURFACE DEW POINT DEPRESSIONS. MODEL INITIALIZATIONS DID A REASONABLE
JOB WITH A COUPLE OF EXCEPTIONS. 500MB TEMPS LOOK A LITTLE WARM ON
ALL MODELS AND THE AVN WAS TOO AGGRESSIVE WITH THE BOUNDARY LAYER
MOISTURE ACROSS THE CWA.

COLD AIR ADVECTION AT 500MB ALONG WITH LOW-LEVEL HEATING WILL
INCREASE LAPSE RATES ACROSS THE CWA TODAY. WE EXPECT ISOLATED
TO SCATTERED SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE AREA
TONIGHT. CURRENT FORECAST HAS A GOOD HANDLE ON THE SITUATION AND
ONLY ADJUSTMENTS TO FIRST PERIOD WILL BE BASED ON RADAR TRENDS.
UPPER FLOW VEERS FROM NW TO N ON MONDAY WHILE LOW LEVEL FLOW BACKS
TO A MORE SELY DIRECTION. EXCEPTION BEING THE WESTERN CWA WHERE
MODELS SHOWING SOME DRIER AIR IN PLACE. MAY HAVE TO TRIM THE ALREADY
SLIM POPS THERE. DO NOT SEE ANY SURFACE BOUNDARIES TO SERVE AS A
FOCUSING MECHANISM FOR MONDAY NIGHT AND WITH 500MB TEMPS WARMING
PRECIP CHANCES WILL BE ON THE DECLINE. GUT FEELING IS TO PULL POPS
FOR TUESDAY AS HIGHER THETA-E AIR SHIFTS WEST...BUT WITH BOUNDARY
LAYER MOISTURE AND DAYTIME HEATING...CAN/T COMPLETELY RULE OUT
PRECIPITATION.

IN THE EXTENDED (WED-SUN)...MODELS CONTINUE TO OFFER DIFFERENT
SOLUTIONS ON HANDLING THE WEST COAST SYSTEM. NEEDLESS TO SAY
CONFIDENCE IS LOW IN THE EXTENDED PERIOD. WE WILL PULL POPS ON
WEDNESDAY AS MODELS INDICATING DRY NORTHERLY FLOW AND WARMING TEMPS
AT THE MID-LEVELS. RIDGE THEN BUILDS OVER AZ FOR SOME WEAK NW FLOW
ALOFT. PREVIOUS MRF BROUGHT A COLD FRONT INTO THE CWA EARLY FRIDAY.
LATEST RUN ALONG WITH THE AVNX HAS SLOWED THE PROGRESS OF THIS
FRONT. CONFIDENCE NOT HIGH EITHER WAY...BUT WITH THE NOGAPS AND
CANADIAN TRENDING THIS WAY WILL ADJUST FORECAST FOR A SLOWER
FRONTAL PASSAGE.

PRELIM CCF...

AMA 62/88 62/85 61 323
DHT 57/86 59/84 58 313

.AMA...
TX...NONE.
OK...NONE.

PLATT