Wildfire in Texas, April 20, 2011

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
1229 PM CDT WED APR 20 2011

.AVIATION...
FOR THE 18Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST THE
FIRST 6 TO 9 HOURS. AFTER 00Z...NORTHEASTERLY WINDS WILL SHIFT TO
EASTERLY THEN SOUTHEASTERLY. THIS MOIST LOW LEVEL UPSLOPE FLOW WILL
SET THE STAGE FOR LOW STRATUS AND BR DEVELOPMENT ACROSS THE
PANHANDLES. EXPECT THE LOW STRATUS DECK TO ADVECT IN FROM THE
SOUTHEAST AND AFFECT THE SOUTHERN AND EASTERN TX
PANHANDLE...INCLUDING KAMA. KAMA SHOULD REMAIN VFR THROUGH
06Z...THOUGH THERE IS SOME UNCERTAINTY IN THE TIMING. ELSEWHERE IN
THE PANHANDLES...INCLUDING KDHT AND KGUY...WHERE THE STRATUS WILL BE
LATE IN ARRIVING...IF AT ALL...THE THREAT WILL BE MORE BR THAN LOW
STRATUS. COULD SEE IFR OR LOWER CONDITIONS IN THESE LOCATIONS...BUT
STILL REMAINS QUITE A BIT OF UNCERTAINTY.

JOHNSON
&&

.PREV DISCUSSION... /ISSUED 653 AM CDT WED APR 20 2011/

AVIATION...
NORTHEASTERLY WINDS WILL BECOME MORE EASTERLY AND EVENTUALLY
SOUTHEASTERLY BY THE LATTER HALF OF THE TAF CYCLE. EASTERLY WINDS TO
PICK UP BY 16Z TO AROUND 15 KNOTS WITH GUSTS BETWEEN 20 AND 22 KNOTS
IN THE AFTERNOON. WINDS WILL BECOME MORE SOUTHEASTERLY UPSLOPE AFTER
00Z WITH THE THREAT OF LOW CLOUDS ESPECIALLY AT AMA. NAM/GFS TIME
HEIGHT CROSS SECTIONS DEPICT INCREASING LOW LEVEL MOISTURE DURING
THIS TIME. FOR NOW..WENT AHEAD AND INTRODUCED A SCATTERED DECK AFTER
06Z BUT MVFR CIGS MAY NEED TO BE INCLUDED IN LATER FORECASTS. WINDS
WILL SUBSIDE TO AROUND 10 KNOTS AFTER 00Z.

PREV DISCUSSION... /ISSUED 434 AM CDT WED APR 20 2011/

DISCUSSION...
RAIN/THUNDERSTORM CHANCES LATE TONIGHT THROUGH THURSDAY NIGHT AND
THIS UPCOMING WEEKEND ARE THE MAIN CHALLENGES.

LATEST MODELS WERE IN GOOD AGREEMENT THROUGH THURSDAY NIGHT...THEN
DIVERGED SIGNIFICANTLY. PREFERRED A 00/06Z NAM12 AND 00Z ECMWF BLEND.

THE BIGGEST CHANGES TO THE PREVIOUS FORECAST WERE TO ADD SLIGHT
CHANCE OF LIGHT RAIN ACROSS THE EAST PANHANDLES AND PATCHY
FOG/DRIZZLE ELSEWHERE LATE TONIGHT INTO THURSDAY MORNING AS WELL
AS REMOVED RAIN CHANCES ON SATURDAY.

AT 430 AM ACROSS THE PANHANDLES...COOL AND HUMID CONDITIONS WERE
OCCURRING WITH SURFACE TEMPERATURES BETWEEN 41 AND 54 DEGREES AND
SURFACE DEWPOINTS IN THE UPPER 30S AND LOWER 40S. A COLD FRONT WAS
SOUTH OF THE PANHANDLES...NEAR A ROSWELL NEW MEXICO TO WACO TEXAS
LINE WHILE A SURFACE RIDGE OF HIGH PRESSURE WAS OVER THE CENTRAL AND
NORTHERN PLAINS.

TODAY...COOLER CONDITIONS CAN BE EXPECTED WITH AN EAST TO SOUTHEAST
UPSLOPE COOL MOIST LOW LEVEL FLOW. WITH A GOOD AMOUNT OF SUN EXPECTED
ESPECIALLY THIS AFTERNOON...LEANED TOWARDS THE SLIGHTLY WARMER 00Z
MAVMOS HIGHS MAINLY IN THE 60S ACROSS THE AREA...GENERALLY 10 TO 15
DEGREES COOLER THAN TUESDAY.

TONIGHT INTO THURSDAY MORNING...LATEST MODELS WERE IN GOOD AGREEMENT
WITH MOIST EAST/SOUTHEAST FLOW. MODEL SOUNDINGS DEPICTED INCREASING
MOISTURE BELOW 700 MB...WHICH IS FORECAST TO BE DEEP ENOUGH...
3000-5000 FT...TO PRODUCE VERY LIGHT RAIN/DRIZZLE/FOG OVER THE
AREA...ESPECIALLY BETWEEN 4 AND 10 AM. KEPT 20 PERCENT CHANCE FOR
LIGHT RAIN OVER THE EAST PANHANDLES...OFF THE CAPROCK...WHERE
MOISTURE WILL BE DEEPEST. THINK THE AIR WILL REMAIN CAPPED FOR
THUNDERSTORM DEVELOPMENT WITH THE POSSIBLE EXCEPTION NEAR THE FAR
EAST TEXAS PANHANDLE/OKLAHOMA STATE LINE. DID NOT MENTION THUNDER AT
THIS TIME THINKING ANY THUNDER WILL STAY EAST OF THE FORECAST AREA.
CONFIDENCE OF WIDESPREAD DENSE FOG IS LOW DUE TO LATEST MODELS
FORECASTING SURFACE WINDS 10-15 MPH WHICH SHOULD KEEP THE AIR NEAR
THE SURFACE SLIGHTLY MIXED. PREFERRED THE WARMER 00Z MAVMOS LOWS IN
THE 40S.

THURSDAY AFTERNOON AND NIGHT...WILL CONTINUE TO MONITOR FOR POSSIBLE
THUNDERSTORM DEVELOPMENT ALONG AND JUST EAST OF THE DRYLINE. FOR
NOW...KEPT 20 PERCENT FOR STORMS EAST OF A GUYMON TO CLAUDE LINE.
LATEST MODELS DEPICTED A WEAK MID LEVEL DISTURBANCE MOVING ACROSS
THE AREA DURING THIS TIME FRAME...WHICH MAY CAUSE JUST ENOUGH LIFT
FOR ISOLATED STORM DEVELOPMENT. ON THE OTHER HAND...FORCING APPEARED
RATHER WEAK AND FORECAST SOUNDINGS DEPICTED A RATHER STRONG LOW LEVEL
CAP TO OVERCOME. MANY MODEL SOLUTIONS DEPICTED NO QPF/RAINFALL
WHATSOEVER. IF STORMS COULD DEVELOP...THEY COULD BE SEVERE WITH LARGE
HAIL THE MAIN HAZARD...THOUGH DAMAGING WINDS AND/OR A BRIEF TORNADO
WOULD BE POSSIBLE. FORECAST CONFIDENCE REMAIN VERY LOW. WENT NEAR 00Z
MAVMOS HIGHS...WHICH MAY BE TOO COOL...ESPECIALLY WEST OF THE
DRYLINE.

FRIDAY THROUGH SATURDAY...DRY CONDITIONS ARE EXPECTED DURING THIS
TIME FRAME. PREFERRED THE 00/06Z NAM12 WHICH DEPICTED A COLD FRONT
SLOWLY MOVING SOUTH AND THROUGH THE AREA FRIDAY AND FRIDAY
NIGHT. COOLER CONDITIONS ARE FORECAST ON SATURDAY. REMOVED RAIN
CHANCES ON SATURDAY WITH NO ELEVATED INSTABILITY OR DEEP MOISTURE
FORECAST OVER THE AREA.

SATURDAY NIGHT THROUGH SUNDAY NIGHT...KEPT 20 PERCENT FOR SHOWERS AND
STORMS DURING THIS TIME FRAME AS LATEST MODELS SUGGESTED INCREASING
MOISTURE...LIFT...AND INSTABILITY ACROSS THE AREA. BASED ON 00Z
NAM12/ECMWF...MOST...IF NOT ALL...CONVECTION MAY BE ELEVATED LATE
SATURDAY NIGHT INTO SUNDAY MORNING...POSSIBLY BECOMING SURFACE BASED
SUNDAY AFTERNOON AND NIGHT IF A WARM FRONT COULD SURGE NORTH.
CONFIDENCE FOR SEVERE STORMS APPEAR QUITE LOW...AND BEST
MOISTURE...LIFT...AND INSTABILITY MAY BE EAST OF THE AREA. WENT BELOW
THE 00Z MEXMOS TEMPERATURES DURING THIS TIME FRAME.

MONDAY THROUGH TUESDAY...KEPT A DRY FORECAST...THOUGH FORECAST
CONFIDENCE REMAINS VERY LOW WITH MUCH MODEL DISAGREEMENT. KEPT
TEMPERATURES NEAR OR BELOW AVERAGE FOR NOW.

MBS

FIRE WEATHER...
HIGHER HUMIDITY AND COOLER TEMPERATURES WILL KEEP FIRE WEATHER
CONDITIONS BELOW ELEVATED OR CRITICAL LEVELS TODAY.

ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS CAN BE EXPECTED
ACROSS THE FAR WEST PANHANDLES THURSDAY AFTERNOON INTO
EARLY EVENING...MAINLY WEST OF A BOISE CITY TO HEREFORD LINE. DID NOT
ISSUE A FIRE WEATHER WATCH FOR THESE LOCATIONS AT THIS TIME AS NOT
SURE EXACTLY HOW FAR EAST THE DRYLINE WILL MOVE AND HAVE LOW
CONFIDENCE OF THESE LOCATIONS MEETING RED FLAG CONDITIONS...RELATIVE
HUMIDITY LEVELS 15 PERCENT OR LESS AND SURFACE WINDS 20 MPH OR
GREATER FOR 3 HOURS OR MORE.

ELEVATED TO PERHAPS CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE
FRIDAY MAINLY SOUTH OF A DALHART TO AMARILLO TO CLAUDE LINE...BUT
THIS REMAINS DEPENDENT ON THE POSITION OF A NEARBY COLD FRONT.

MBS

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.

&&

16/13

HAZARDOUS WEATHER OUTLOOK...RESENT
NATIONAL WEATHER SERVICE AMARILLO TX
532 AM CDT WED APR 20 2011

OKZ001>003-TXZ001>020-202100-
CIMARRON-TEXAS-BEAVER-DALLAM-SHERMAN-HANSFORD-OCHILTREE-LIPSCOMB-
HARTLEY-MOORE-HUTCHINSON-ROBERTS-HEMPHILL-OLDHAM-POTTER-CARSON-
GRAY-WHEELER-DEAF SMITH-RANDALL-ARMSTRONG-DONLEY-COLLINGSWORTH-
532 AM CDT WED APR 20 2011

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...THURSDAY THROUGH TUESDAY.

ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE THURSDAY
ACROSS THE WESTERN TEXAS AND OKLAHOMA PANHANDLES DUE TO STRONG WINDS
AND LOW RELATIVE HUMIDITY VALUES.

THUNDERSTORMS WILL BE POSSIBLE THURSDAY AFTERNOON AND NIGHT ACROSS
THE CENTRAL AND EASTERN PANHANDLES. ANY STORM THAT DEVELOPS MAY
BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS AS THE PRIMARY
THREATS.

ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE FRIDAY
ACROSS THE SOUTHWESTERN TEXAS PANHANDLE DUE TO STRONG WINDS AND LOW
RELATIVE HUMIDITY VALUES.

THUNDERSTORMS WILL BE POSSIBLE SATURDAY NIGHT THROUGH SUNDAY NIGHT
ACROSS MUCH OF THE PANHANDLES. SOME STORMS MAY BE STRONG WITH SMALL
HAIL.

.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 THURSDAY AND FRIDAY
MAINLY ACROSS WESTERN PORTIONS OF THE PANHANDLES.

TAB