Severe Thunderstorm Warning 176, NWS Amarillo, TX

TEXAS/OKLAHOMA PANHANDLES FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AMARILLO TX
357 AM CDT MON SEP 17 2001

LATEST SURFACE ANALYSIS SHOWING LOW PRESSURE CENTERED OVER
SOUTHEAST COLORADO NEAR KLAA. A STATIONARY FRONT WAS STRETCHED FROM
JUST SOUTH OF KGLD TO KHLC THEN INTO EAST CENTRAL KS. WATER VAPOR
IMAGERY SHOWING AN UPPER LEVEL LOW MOVING EAST ALONG THE ID/NV STATE
LINE. MODELS GENERALLY INITIALIZED WELL...ALTHOUGH 850MB DEW POINTS
LOOK TOO LOW OVER CENTRAL TX AND 300MB WIND SPEEDS LOOK TO LOW IN
THE WESTERN U.S. WHEN COMPARED TO 17/00Z RAOBS.

IN GENERAL...THE CURRENT FORECAST LOOKS GOOD AND WILL ONLY MAKE
MINOR CHANGES. AT THE MID-LEVELS...WLY FLOW WILL BE INCREASING TODAY
ADVECTING COOLER AIR INTO THE REGION SERVING TO STEEPEN LAPSE RATES.
SOUTHERLY WINDS AT THE SURFACE WILL KEEP DEW POINTS IN THE UPPER 50S
WEST TO AROUND 65 EAST. THE MOST FAVORABLE PARAMETERS FOR
CONVECTION WILL INITIALLY BE OVER THE WESTERN ZONES WITH LOW-
LEVEL CONVERGENCE IN THE VICINITY OF THE ABOVE MENTIONED SURFACE LOW
AND INCREASING UPPER LEVEL DIVERGENCE ASSOCIATED WITH A 65KT 300MB
JET STREAK. CONVECTION WILL SPREAD EAST AND INCREASE THIS EVENING AND
INTO TONIGHT AS IN ENCOUNTERS A COLD FRONT...HIGHER BOUNDARY
LAYER DEW POINTS AND LOW-LEVEL JET. MODELS ALSO DEPICTING SOME
DRIER AIR IN THE 700MB-500MB LAYER MOVING IN TONIGHT WHICH WOULD
ENHANCE THE HAIL POTENTIAL. THE COLD FRONT SHOULD MAKE STEADY
PROGRESS THROUGH THE CWA TONIGHT AND IS EXPECTED TO BE LOCATED OVER
OUR FAR SOUTHERN TIER BY EARLY TUESDAY MORNING. NORTHERLY LOW-LEVEL
FLOW WILL INCREASE ON TUESDAY USHERING COOLER AIR INTO THE REGION.
MODELS DO NOT COMPLETELY SCOUR OUT LOW-LEVEL MOISTURE...AND WITH
500MB TEMPS AROUND -11C CAN/T RULE THE POSSIBILITY OF CONVECTION
TUESDAY INTO TUESDAY NIGHT. CONVECTION DOES NOT LOOK PARTICULARLY
FAVORABLE ON WEDNESDAY AS SURFACE HIGH PRESSURE BUILDS OVER THE
AREA...HOWEVER DON/T FEEL COMFORTABLE PULLING POPS WITH NORTHWEST
FLOW ALOFT.

A BREAK IN THE PRECIP STILL LOOKS GOOD FOR THURSDAY. WILL HAVE TO
KEEP AN EYE ON MOISTURE RETURN AS THE FRONT STALLS OVER THE
PERMIAN BASIN. SOUTHERLY WINDS TO RETURN MOISTURE TO THE AREA
BEGINNING LATE THURSDAY. CURRENT EXTENDED LOOKS GOOD AND WILL LET IT
RIDE.

AMA 86/60 78/55 81 363
DHT 85/56 76/52 79 353

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

PLATT

OKZ001>003-TXZ001>020-172100-

TEXAS/OKLAHOMA PANHANDLES THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE AMARILLO TX
1255 PM CDT MON SEP 17 2001

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE ENTIRE
TEXAS AND OKLAHOMA PANHANDLES THROUGH TONIGHT.

WARM...MOIST...UNSTABLE AIR WILL BE FOUND ACROSS THE PANHANDLES THIS
AFTERNOON. A SURFACE TROUGH ACROSS EASTERN NEW MEXICO WILL MOVE EAST
INTO THE WESTERN PANHANDLES BY MID AFTERNOON.  A COLD FRONT WILL MOVE
ACROSS THE PANHANDLES TONIGHT. THE WARM...MOIST AND UNSTABLE AIRMASS
WILL BE LIFTED BY THESE SURFACE BOUNDARIES AND AN UPPER LEVEL
DISTURBANCE WILL MOVE FROM THE ROCKIES INTO THE PANHANDLES TO PROVIDE
A TRIGGER FOR THUNDERSTORM DEVELOPMENT.

THUNDERSTORMS ARE EXPECTED TO DEVELOP IN SOUTHEAST COLORADO OR
NORTHEAST NEW MEXICO BY MID AFTERNOON. THESE STORMS ARE THEN EXPECTED
TO MOVE EAST INTO PANHANDLES.  THE UNSTABLE AIR ALONG WITH THE UPPER
LEVEL ENERGY WILL PROVIDE THE STAGE FOR STRONG TO SEVERE THUNDERSTORM
DEVELOPMENT THROUGH TONIGHT. THE MAIN THREATS FROM THE STORMS WILL BE
LARGE HAIL AND VERY HEAVY RAIN. HEAVY RAIN HAS ALREADY FALLEN ACROSS
PARTS OF THE WESTERN AND CENTRAL TEXAS PANHANDLE AND THE CENTRAL
OKLAHOMA PANHANDLE OVER THE LAST COUPLE OF DAYS. MORE HEAVY RAIN WILL
ONLY AGGRAVATE THE FLASH FLOOD POTENTIAL.

ISOLATED SUPERCELLS WITH TORNADOES WILL ALSO NOT BE OUT OF THE
QUESTION AS THE WIND PROFILE ALOFT BECOMES MORE FAVORABLE THIS
AFTERNOON.

SPOTTERS AND EMERGENCY MANAGEMENT OFFICIALS SHOULD REMAIN ALERT FOR
POSSIBLE ACTIVATION THIS AFTERNOON OR EVENING.

GOEHRING