FXUS64 KSJT 112322
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
622 PM CDT SUN MAY 11 2008



.AVIATION...
EXPECT VFR CONDITIONS TO CONTINUE OVER THE NEXT 24 HOURS...HIGH
CLOUD CANOPY TO STAY AROUND THROUGH THIS EVENING AND WILL BEGIN TO
SCATTER OUT OVERNIGHT AND WILL REMAIN SCT MONDAY. AS A SURFACE
HIGH PRESSURE SYSTEM SHIFT EAST INTO EAST TEXAS...LOW LEVEL WINDS
WILL SHIFT TO THE SOUTH EAST THIS EVENING AND TO THE SOUTH MONDAY
MORNING. A LEE SIDE TROUGH WILL BRING GUSTY SOUTH WINDS AT 15 TO
20 KNOTS WITH HIGHER GUSTS LATE MONDAY MORNING INTO EARLY EVENING.

&&

.PREV DISCUSSION... /ISSUED 301 PM CDT SUN MAY 11 2008/

DISCUSSION...

THE 12Z/11 GFS AND 00Z/11 ECMWF ARE IN PRETTY GOOD AGREEMENT
OVERALL AND ARE NOT MUCH DIFFERENT FROM THEIR FORECASTS YESTERDAY
AT THIS TIME. THE ONLY GLARING DIFFERENCE INVOLVES THE TIMING OF
THE MIDWEEK UPPER LOW ACROSS TX...WITH THE GFS BEING FASTER. SO
THERE IS NOT MUCH MORE TO ADD FROM MY DISCUSSION YESTERDAY.
SIGNIFICANT AMPLIFICATION OF THE UPPER FLOW PATTERN WILL OCCUR
OVER THE NEXT COUPLE OF DAYS IN THE FORM OF A RIDGE ALONG THE WEST
COAST AND A SHORTWAVE DIGGING SOUTH INTO THE FOUR CORNERS ON
TUESDAY. THIS AMPLIFICATION WILL CONTINUE THROUGH THE END OF THE
WEEK...WITH ANOTHER SHORTWAVE TROUGH EXPECTED TO MOVE ACROSS TEXAS
THURSDAY NIGHT INTO FRIDAY.

BEFORE THIS OCCURS...MOISTURE WILL RETURN NORTH DURING THE DAY
MONDAY AS WHAT IS LEFT OF TODAY'S COLD FRONT LIFTS BACK NORTH AS A
WARM FRONT. THERE WILL BE A SMALL CHANCE OF AN ISOLATED STORM OR TWO
OVER THE DAVIS AND NORTHERN MEXICO MOUNTAINS DURING PEAK HEATING BUT
CHANCES OF THIS GETTING INTO MY AREA ARE TOO SMALL AT THIS POINT TO
MENTION IN FORECAST. THERE IS ALSO A SMALL CHANCE OF ELEVATED
CONVECTION MONDAY NIGHT BUT ONCE AGAIN CHANCES ARE TOO SMALL TO
MENTION AT THIS POINT.

AS THE SYSTEM DIGS INTO THE FOUR CORNERS TUESDAY...SOUTHWEST FLOW
WILL DEVELOP OVER TEXAS AND A DRYLINE WILL MIX EAST INTO THE AREA
DURING THE AFTERNOON. THERE WILL CONTINUE TO BE SLGT CHCS OF STORMS
AHEAD OF THE DRYLINE WHICH COULD BECOME SEVERE. THEN...AS THE SYSTEM
APPROACHES FROM THE WEST TUESDAY NIGHT INTO WEDNESDAY...A COLD FRONT
WILL DROP SOUTH INTO THE REGION AND WILL BE THE FOCUS FOR STRONG TO
SEVERE THUNDERSTORM ACTIVITY WHICH MAY CONGEAL INTO AN MCS THAT
MOVES ACROSS TEXAS DURING THE OVERNIGHT INTO WEDNESDAY MORNING. SOME
OTHER STORMS ARE POSSIBLE WEDNESDAY AFTERNOON BENEATH THE COLD CORE
UPPER SYSTEM AS IT MOVES ACROSS...ALTHOUGH THE ECMWF IS SLOWER AND
DOES NOT BRING IT ACROSS TILL WEDNESDAY NIGHT AS AN OPEN WAVE.
BOTTOM LINE...BEST CHANCES FOR STORMS WILL BE TUESDAY NIGHT INTO
WEDNESDAY...POSSIBLY CARRYING OVER INTO WEDNESDAY NIGHT IF THE 00Z
ECMWF VERIFIES.

THE UPPER FLOW BECOMES NORTHERLY ACROSS THE PLAINS LATE IN THE
WEEK AS THE RIDGE CONTINUES TO AMPLIFY AND SHIFT EAST INTO THE
WESTERN CONUS. AS THIS OCCURS...ANOTHER PIECE OF SHORTWAVE ENERGY
(THE TIMING OF WHICH IS IN AGREEMENT BETWEEN GFS/ECMWF) WILL DIVE
SOUTH INTO TEXAS THURSDAY OR THURSDAY NIGHT AND WILL BRING A
CHANCE FOR SHOWERS AND MAYBE AN ISOLATED STORM. THE MOIST UNSTABLE
AIR WILL BE DISPLACED TO THE SOUTHEAST OVER THE GULF BY THIS
TIME...SO A SEVERE EPISODE IS NOT EXPECTED.

TEMPERATURE WISE...WARMING TREND THRU TUESDAY WHICH WILL BE THE
WARMEST DAY BEHIND THE DRYLINE AS IT MIXES EAST BASED ON PRONGED
850MB TEMPS IN THE MID TO UPPER 20S CELSIUS. COOLER TEMPS ARE
EXPECTED WEDNESDAY BEHIND THE FRONT AND WITH CLOUDS/PRECIP AROUND.
THURSDAY AND FRIDAY WILL BE COOLER THAN NORMAL WITH THE SECOND
SHORTWAVE TROUGH EMBEDDED IN THE NORTHERLY FLOW HELPING TO BRING
DOWN SOME COOLER CANADIAN AIR INTO THE AREA.

FIRE WEATHER...

LIGHT WINDS UNDER HIGH PRESSURE WILL PREVAIL THROUGH TONIGHT. WARMER
AND DRIER WEATHER WILL RETURN TO THE AREA MONDAY INTO TUESDAY.
RELATIVE HUMIDITY VALUES WILL DROP INTO THE 15 TO 20 PERCENT RANGE
GENERALLY WEST OF A LINE FROM SWEETWATER TO BARNHART ON MONDAY.
WHILE WINDS WILL PICK UP AS A SURFACE LOW INTENSIFIES NORTH OF THE
AREA...FEEL THAT THE DURATION OF ANY RED FLAG CONDITIONS WILL NOT BE
LONG ENOUGH. FARTHER TO THE EAST...GREEN FUELS CONDITIONS AND HIGHER
RELATIVE HUMIDITY VALUES WILL PRECLUDE ANY RED FLAG WARNINGS. ON
TUESDAY...HOTTER TEMPERATURES WILL DRIVE RH VALUES DOWN TO NEAR
SINGLE DIGIT VALUES...BUT THE SURFACE PRESSURE PATTERN WILL RESULT
IN WINDS LIGHTER THAN 20 MPH AT 20 FEET ACROSS THE AREA. THERE IS
ALSO A CHANCE FOR THUNDERSTORMS BEGINNING TUESDAY AFTERNOON...AND
CONTINUING THROUGH WEDNESDAY NIGHT. MOST OF THESE STORMS WILL BE
EAST OF A LINE FROM SWEETWATER TO SONORA.

A COLD FRONT WILL MOVE THROUGH TUESDAY NIGHT INTO WEDNESDAY
MORNING...FOLLOWED BY A REINFORCING SHOT OF COOL AIR WEDNESDAY
NIGHT. THIS WILL COOL TEMPERATURES THROUGH THE SECOND HALF OF THE
WEEK... RAISING RH VALUES. LIGHTER WINDS WILL ALSO BE IN PLACE IN
THE WAKE OF THESE FRONTS...DIMINISHING FIRE WEATHER DANGER FROM
WEDNESDAY THROUGH FRIDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
ABILENE 	 52  89  69  90 /   0   0  10  20
SAN ANGELO 	 53  92  71  95 /   0  10  10  10
JUNCTION 	 51  90  70  93 /   0   0  10  20

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

99/99/28