Area Forecast Discussion
Issued by NWS Amarillo, TX

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000
FXUS64 KAMA 282315
AFDAMA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AMARILLO TX
615 PM CDT SAT MAR 28 2015

.AVIATION...
VFR CONDITIONS TO PREVAIL THROUGH THE 00Z TAF CYCLE WITH A COLD FRONT
PASSAGE THE MAIN AVIATION CONCERN. LIGHT SURFACE WINDS OF LESS THAN
12KT ARE EXPECTED TO PERSIST THROUGH THE OVERNIGHT HOURS. A COLD
FRONT IS EXPECTED TO MOVE THROUGH THE TERMINALS BETWEEN 13Z AND 15Z.
BEHIND THE FRONT NORTH WINDS OF 25KTS WITH GUSTS UP TO 35KT ARE
EXPECTED. TOWARDS 00Z TOMORROW WINDS SHOULD BEGIN TO DIMINISH.

&&

.PREV DISCUSSION... /ISSUED 350 PM CDT SAT MAR 28 2015/

DISCUSSION...

EARLY THIS AFTERNOON THE RAP SEEMED TO BEST REPRESENT SURFACE WIND AND
PRESSURE FIELDS WITH ONLY MINOR DIFFERENCES AMONG SHORT TERM
GUIDANCE. LIGHT NORTHWESTERLY SURFACE WINDS PREVAILED AS ONLY WEAK
LEE TROUGHING WAS PRESENT. WATER VAPOR LOOP SHOWS NORTHWESTERLY FLOW
ALOFT BETWEEN RIDGING IN THE WEST AND DEEP TROUGHING IN THE EAST.

A SHORTWAVE TROUGH WILL QUICKLY PASS THROUGH THE CENTRAL PLAINS
TOMORROW AND ITS ASSOCIATED SURFACE FRONT WILL MOVE THROUGH THE
PANHANDLES DURING THE MORNING. BEHIND THE FRONT A PERIOD OF
ISALLOBARIC WIND SUSTAINED AT ABOUT 20 TO 30 MPH WILL OCCUR WITH
GUSTS APPROACHING 40 MPH. PRESSURE RISES ARE NOT AS INTENSE AS
PREVIOUS FRONTAL PASSAGE EARLIER THIS WEEK WHICH RESULTED IN STRONGER
WINDS AND SOME AREAS OF BLOWING DUST NEAR OPEN FIELDS. ANY BLOWING
DUST SHOULD BE LOCALIZED AND RELATIVELY INSIGNIFICANT.

THE LARGE SCALE PATTERN IS EXPECTED TO DEAMPLIFY AND EVOLVE INTO A
PROGRESSIVE QUASI-ZONAL FLOW PATTERN THROUGH NEXT WEEK. STRENGTHENING
MEAN WESTERLIES WILL RESULT IN A SHARPENING OF THE LEE SURFACE TROUGH
AND INCREASE IN SOUTHERLY FLOW. MODELS MAY BE TOO AGGRESSIVE WITH LOW
LEVEL MOISTURE RETURN BUT THE CONSENSUS IS FOR HIGHER DEW POINTS TO
ADVECT NORTHWARD LATE TUESDAY. AS THIS OCCURS BENEATH STEEPENING MID
LEVEL LAPSE RATES AND MODEST DEEP LAYER FLOW AS A WEAK SOUTHERN
STREAM UPPER LEVEL WAVE PASSES...ORGANIZED ISOLATED/SCATTERED
DIURNALLY DRIVEN CONVECTION MAY OCCUR. THIS WOULD HAPPEN PRIMARILY
ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA GIVEN EXPECTED
POSITION OF LEE TROUGH/DRYLINE.

CONFIDENCE IN HOW SURFACE FEATURES EVOLVE MID WEEK IS A LITTLE LESS
THEN DESIRABLE AS WESTERLY FLOW ALOFT STRENGTHENS WITH WEAK
PERTURBATIONS EMBEDDED WITHIN. THE GENERAL CONSENSUS IS FOR A WEAK
LEE LOW TO EVOLVE AND SHIFT EASTWARD LEADING TO DRY LOW LEVELS ACROSS
THE FORECAST AREA. MUCH STRONGER LEE SURFACE CYCLOGENESIS OCCURS AS A
TROUGH DEEPENS IN THE WEST BY THE END OF THE WEEK BUT SPATIAL AND
TEMPORAL DETAILS ARE UNCLEAR AT THIS RANGE AND IT CURRENTLY APPEARS
THAT HIGHER PRECIPITATION PROBABILITIES WILL BE NORTH AND EAST OF
THE AREA THROUGH THE END OF THE FORECAST PERIOD.

BRB

FIRE WEATHER...

A COLD FRONT WILL MOVE SOUTH THROUGH THE AREA TOMORROW MORNING BRINGING
AN INCREASE IN WIND SPEEDS AND SLIGHTLY COOLER TEMPERATURES. 20 FOOT
WIND SPEEDS WILL INCREASE BY LATE MORNING AND CONTINUE INTO THE EARLY
AFTERNOON. COINCIDENTALLY AS TEMPERATURES WARM RELATIVE HUMIDITY VALUES
WILL FALL TO A MINIMUM OF AROUND 20 PERCENT. THIS MAY RESULT IN A PERIOD
OF ELEVATED FIRE WEATHER CONDITIONS FROM MIDDAY THROUGH LATE AFTERNOON.

BRB

&&

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

&&

$$

14/15





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