Area Forecast Discussion
Issued by NWS Amarillo, TX

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000
FXUS64 KAMA 200402 AAC
AFDAMA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
1102 PM CDT SUN APR 19 2015

.AVIATION...
FOR THE 06Z TAFS...GENERALLY LIGHT WINDS AND INCREASING MID-LEVEL
CLOUDS THROUGH MONDAY MORNING FOR ALL TAF SITES. THEN WINDS WILL
BECOME SOUTHERLY AND INCREASE TO AROUND 10 TO 15 KTS THROUGH THE
AFTERNOON. THERE IS A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS TO
IMPACT THE TAF SITES BETWEEN 00Z AND 06Z...THOUGH CHANCES ARE TOO LOW
TO INCLUDE IN TAFS AT THIS TIME.

NF

&&

.PREV DISCUSSION... /ISSUED 926 PM CDT SUN APR 19 2015/

UPDATE...
HAVE GONE AHEAD AND INCLUDED ROBERTS...GRAY...CARSON AND ARMSTRONG
COUNTIES TO THE FROST ADVISORY. CURRENT TRENDS SHOW TEMPERATURES ARE
JUST AS COOL IF NOT COOLER THAN THE REST OF THE FROST ADVISORY AREA.
LIGHT WINDS ARE EXPECTED TO PREVAIL IN THESE AREAS WITH CLOUDS
INCREASING LATE. SO TEMPERATURES SHOULD CONTINUE TO DROP FAIRLY QUICKLY.

PREV DISCUSSION... /ISSUED 655 PM CDT SUN APR 19 2015/

AVIATION...
FOR THE 00Z TAFS...GUSTY NORTH WINDS SHOULD SEE SPEEDS CONTINUE TO
DECREASE THE REST OF THIS EVENING...DROPPING TO BELOW 12 KTS AT ALL
SITES BY AROUND 02Z. AT KAMA AND KDHT...WINDS COULD BECOME LIGHT AND
VARIABLE OVERNIGHT AS THEY GRADUALLY SPIN AROUND TO SOUTHERLY BY MID
MONDAY MORNING. NORTHERLY WINDS SHOULD HOLD ON LONGER AT
KGUY...BECOMING SOUTH TO SOUTHEASTERLY BY THE AFTERNOON HOURS ON
MONDAY. MID- LEVEL CLOUDS WILL CONTINUE TO BUILD INTO THE REGION FROM
WEST TO EAST THROUGH THE PERIOD...AND A FEW SHOWERS OR THUNDERSTORMS
COULD IMPACT KDHT OR KGUY BY THE VERY END OF THIS TAF PERIOD.

NF

PREV DISCUSSION... /ISSUED 424 PM CDT SUN APR 19 2015/

DISCUSSION...

MOST GUIDANCE HAS HAD A WARM BIAS FOR THE PREVIOUS COUPLE OF NIGHTS.
LOW TEMPERATURES IN THE MID 30S SEEM PROBABLE FOR ALL BUT THE
SOUTHEASTERN TEXAS PANHANDLE TONIGHT GIVEN EXPECTED LIGHT WINDS AS
SURFACE HIGH MOVES OVER IN THE WAKE OF DEPARTING UPPER LEVEL
SHORTWAVE. ONE CAVEAT IS EXPECTED MID LEVEL CLOUDS THAT WILL
INCREASE LATER TONIGHT AS A WEAK SHORTWAVE TROUGH APPROACHES IN
NORTHWESTERLY FLOW ALOFT. NOT CONFIDENT IN A WIDESPREAD SIGNIFICANT
FROST IN THIS SCENARIO BUT FEEL THAT THERE IS SUFFICIENT POTENTIAL
TO JUSTIFY A FROST ADVISORY. THE ADVISORY STARTS AT 3 AM AND
CONTINUES THROUGH 10 AM.

PERIODIC SMALL AND DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN
NORTHWESTERLY FLOW ALOFT OVER THE NEXT FEW DAYS WILL RESULT IN
CHANCES FOR SHOWERS AND THUNDERSTORMS. HI-RES CONVECTION ALLOWING
GUIDANCE IS PARTICULARLY AGGRESSIVE WITH DEVELOPING CONVECTION
TOMORROW AFTERNOON AND NIGHT ACROSS THE AREA. THIS IS DRIVEN
PRIMARILY BY SUBTLE FORCING FROM AFOREMENTIONED WAVES AND LOW LEVEL
WARM MOIST ADVECTION. UPPER FLOW PATTERN AMPLIFIES MID TO LATE WEEK
AS RIDGING BUILDS AHEAD OF A DEEPENING TROUGH IN THE WEST. BUT WITH
A QUASI-STATIONARY SURFACE BOUNDARY POSITIONED ACROSS THE AREA
PARALLEL TO MEAN WEST/NORTHWESTERLY MEAN FLOW...AT LEAST LOW
COVERAGE OF CONVECTION WILL PROBABLY OCCUR BOTH DAYS. DIFFERENCES IN
DETERMINISTIC AND ENSEMBLE GUIDANCE LEADS TO UNCERTAINTY ON FRIDAY
BUT THERE IS ENOUGH OF A SIGNAL OF ANOMALOUS HEIGHTS AND RESULTANT
FORCING IN COMBINATION WITH A NORTHWESTWARD MOVEMENT OF LOW LEVEL
MOISTURE FOR A ORGANIZED PRECIPITATION EVENT AND POSSIBLE SEVERE
THUNDERSTORMS. AMPLITUDE AND GEOMETRY OF THIS UPPER LEVEL WAVE WILL
ULTIMATELY DETERMINE POSITION OF DRYLINE.

BRB

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...FROST ADVISORY FROM 4 AM TO 10 AM CDT MONDAY FOR THE FOLLOWING
     ZONES: ARMSTRONG...CARSON...DALLAM...DEAF SMITH...GRAY...
     HANSFORD...HARTLEY...HUTCHINSON...LIPSCOMB...MOORE...
     OCHILTREE...OLDHAM...POTTER...RANDALL...ROBERTS...SHERMAN.

OK...FROST ADVISORY FROM 4 AM TO 10 AM CDT MONDAY FOR THE FOLLOWING
     ZONES: BEAVER...CIMARRON...TEXAS.


&&

$$

06/15




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