FXUS64 KAMA 030000 AAA
AFDAMA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AMARILLO TX
600 PM CST WED DEC 2 2009

.AVIATION...
PRESSURE GRADIENT WILL RELAX THIS EVENING AS THE HIGH PRESSURE
SYSTEM SETTLES ACROSS THE SURFACE. NORTH WINDS WILL SUBSIDE ACROSS
THE PANHANDLES WITH SPEEDS REMAINING BELOW 15 KTS THROUGH THE
FORECAST. WIND DIRECTION IS EXPECTED TO SHIFT FROM THE EAST ON
THURSDAY ONCE THE CENTER OF THE SURFACE HIGH PRESSURE SLIDES SLOWLY
EAST.

ANOTHER WEATHER DISTURBANCE IS ANTICIPATED TO PUSH THROUGH THE
PANHANDLES THURSDAY AFTERNOON AND EVENING. CEILINGS SHOULD BE
PRIMARILY IN THE VFR CATEGORY...HOWEVER...SOME LOW CLOUDS MAY
DEVELOP. CONFIDENCE IS LOW REGARDING THE IFR THREAT LATE IN THE
FORECAST...SO WE RAISED CEILINGS TO MVFR UNTIL CONFIDENCE IMPROVES.

NUNEZ

&&

.PREV DISCUSSION... /ISSUED 235 PM CST WED DEC 2 2009/ 

DISCUSSION...
THE MOST IMPRESSIVE FEATURE ON THE SYNOPTIC SCALE CONTINUES TO BE 
THE DEEP UPPER LOW MOVE ACROSS THE MID MISSISSIPPI RIVER VALLEY. IN 
ITS WAKE...ANOTHER STRONG UPPER LEVEL CYCLONE IS DIVING SOUTH ACROSS 
THE PLAINS. THIS FEATURE WILL BE OUR NEXT SYSTEM OF CONCERN. THE 
VORT LOBE ALREADY VISIBLE JUST TO THE SOUTHWEST OF THE MAIN LOW WILL 
HELP PROVIDE LIFT FOR SNOWFALL BEGINNING TONIGHT. STRATOCU DECK 
ASSOCIATED WITH DEVELOPING UPSLOPE FLOW AND MODEST ISENTROPIC ASCENT 
HAVE MOVED INTO THE NORTHWEST ZONES. LIGHT SNOW HAS BEEN REPORTED 
ACROSS SOUTHEAST CO FOR THE PAST SEVERAL HOURS AND SHOULD INCREASE 
IN COVERAGE AS IT MOVES SOUTH OVERNIGHT. H7-H5 FRONTOGENESIS...
POSITIONED BENEATH A POCKET OF NEGATIVE EPV...WILL PROVIDE 
SUFFICIENT MESOSCALE FORCING FOR LIGHT TO MODERATE SNOW FOR 
LOCATIONS MAINLY ON THE CAPROCK. THIS FORCING WILL INCREASE THROUGH 
THURSDAY AFTERNOON...SLOWLY SHIFTING SOUTH...BEFORE DIMINISHING 
THURSDAY EVENING WITH SNOW COMING TO AN END BY 12Z FRIDAY. TOTAL 
SNOW ACCUMULATIONS OF 1 TO 2 INCHES WILL BE POSSIBLE IN THE 
WEST...BUT NO WINTER WX HIGHLIGHTS WILL BE ISSUED AT THIS TIME GIVEN 
THE UNCERTAINTY OF WHERE THE HEAVIER SNOW WILL FALL. TEMPS WILL 
REMAIN COLD ON THURSDAY...WITH MANY AREAS ON THE CAPROCK REMAINING 
BELOW FREEZING THROUGHOUT THE DAY.

ON FRIDAY...UNSEASONABLY COLD TEMPS WILL PERSIST AS THE ARCTIC 
AIRMASS WILL BE SLOW TO ERODE. HIGHS ARE ONLY FORECAST TO CLIMB INTO 
THE MID/UPPER 30S. LEE TROFFING WILL INTENSIFY BY SATURDAY AS THE 
FLOW ALOFT BECOMES QUASI ZONAL. SOUTHWEST WINDS WILL INCREASE IN 
RESPONSE TO SURFACE PRESSURE FALLS WITH BREEZY CONDITIONS 
ANTICIPATED DURING THE AFTERNOON. THIS SHOULD HELP WARM TEMPS INTO 
THE MID/UPPER 40S. 

THE RETREATING ARCTIC AIRMASS IS FORECAST TO DIP SOUTH ONCE AGAIN 
INTO THE PANHANDLES ON SUNDAY. TEMPS ARE CURRENTLY EXPECTED TO 
MODERATE ON MONDAY BUT IF THE COLD AIRMASS LOCKS IN ON SUNDAY...
FORECAST TEMPS WILL NEED TO BE LOWERED. THE PATTERN BY 00Z MONDAY 
CONTINUES A PATTERN LOOSELY RESEMBLING THE MCFARLAND SIGNATURE WITH 
MORE COLD AIR LIKELY TO ARRIVE BY TUESDAY. TEMPS ARE EXPECTED TO 
HEAD BY MIDWEEK AS THIS COLD AIR SURGES INTO THE REGION. WITH THE 
FORECAST TRACK OF THE UPPER LOW...LOW POPS HAVE BEEN INCLUDED ACROSS 
MOST OF THE AREA TUESDAY AND TUESDAY NIGHT. 

JOHNSON

FIRE WEATHER...
NO FIRE WEATHER CONCERNS ARE ANTICIPATED DURING THE NEXT 7 DAYS DUE 
TO UNSEASONABLY COOL CONDITIONS.

JOHNSON

&&

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

&&

$$

08/16