Forecast-Discussion
000
FXUS65 KTWC 172147
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
245 PM MST THU MAY 17 2012
.SYNOPSIS...DRY CONDITIONS WITH SEASONABLY HOT DAYTIME TEMPERATURES
WILL PREVAIL INTO THE MIDDLE OF NEXT WEEK. BREEZY TO WINDY
CONDITIONS WILL OCCUR FRIDAY AS A LOW PRESSURE SYSTEM PASSES NORTH
OF THE AREA. BREEZY TO LOCALLY WINDY CONDITIONS MAY RETURN TUESDAY AS
ANOTHER LOW PRESSURE SYSTEM MOVES NORTH OF THE AREA.
&&
.DISCUSSION...UPPER TROUGH ALONG THE CALIFORNIA COAST THIS AFTERNOON
WILL MOVE EWD INTO THE GREAT BASIN REGION TONIGHT. UPPER TROUGH WILL
THEN ADVANCE EWD INTO THE INTERMOUNTAIN WEST FRI. MINOR INCREASE IN
MOISTURE ABOVE 500 MB MAY PRODUCE SOME CIRRIFORM CLOUDS STARTING
THIS EVENING THRU FRI MORNING. THUS MOSTLY CLEAR SKIES TONIGHT AND
FRI MORNING FOLLOWED BY CLEAR SKIES FRI AFTERNOON. MAIN IMPACT WILL
BE BREEZY TO WINDY CONDITIONS PARTICULARLY FRI AFTERNOON AND EARLY
FRI EVENING.
UPPER TROUGH TO MIGRATE INTO THE CENTRAL ROCKIES/CENTRAL CONUS
PLAINS SAT. DRY NWLY FLOW ALOFT SAT WITH MARKEDLY LESS WIND. UPPER
RIDGE TO AMPLIFY OVER THE SWRN CONUS SUN...THEN FLOW ALOFT TO BECOME
INCREASINGLY SWLY MON IN ADVANCE OF THE NEXT UPPER TROUGH ENTERING
THE WEST COAST. MAINLY MID-LEVEL MOISTURE IS PROGGED TO INCREASE
ACROSS ERN SECTIONS BY MON AFTERNOON.
17/12Z GFS WAS MORE PRONOUNCED WITH THIS INCREASED-MOISTURE SCENARIO
VERSUS THE ECMWF. AT THIS APPEARS THAT ANY MEASURABLE PRECIP WILL
REMAIN EAST OF THIS FORECAST AREA. HOWEVER...AM SOMEWHAT CONCERNED
ABOUT THE PROSPECT OF DRY LIGHTNING. AGAIN...AT THIS TIME APPEARS
THAT ANY DRY LIGHTNING WOULD OCCUR MAINLY NEAR THE NEW MEXICO
BORDER. GIVEN THE LOW CONFIDENCE...HAVE OPTED TO PRECLUDE DRY
LIGHTNING FROM THE GRIDDED DATA WEATHER FIELD. MOISTURE TO BE
SHUNTED EWD TUE AS UPPER TROUGH ADVANCES EWD INTO THE INTERMOUNTAIN
WEST. BREEZY TO LOCALLY WINDY CONDITIONS SHOULD RETURN TUE. DRY NWLY
ALOFT TO PREVAIL WED BEHIND THE DEPARTING UPPER TROUGH.
HIGH TEMPS FRI TO AVERAGE ABOUT 5 DEGS F OR SO ABOVE NORMAL. MINOR
COOLING SAT WITH DAYTIME TEMPS TRENDING CLOSE TO NORMAL. WARMER SUN
AND MUCH WARMER MON...WITH HIGH TEMPS IN THE TUCSON METRO AREA TO
APPROACH 105 F. MINOR COOLING TUE-WED ALTHOUGH DAYTIME TEMPS
FORECAST TO REMAIN ABOVE NORMAL.
&&
.AVIATION...SKC-SCT CLOUDS AT OR ABOVE 15K FT AGL THRU FRIDAY
MORNING THEN SKC FRIDAY AFTERNOON. SURFACE WIND MOSTLY LESS THAN 10
KTS TONIGHT. SURFACE WIND FRIDAY SLY/SWLY 12-25 KTS WITH GUSTS TO
35-40 KTS...STRONGEST WIND EAST OF TUCSON PARTICULARLY FRIDAY
AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A RED FLAG WARNING IS IN EFFECT FROM 11 AM TO 8 PM
MST FRIDAY FOR FIRE WEATHER ZONES 146...148...AND EASTERN 147. THE
RED FLAG WARNING INCLUDES ALL OF SOUTHEAST ARIZONA EXCEPT WESTERN
AND CENTRAL PIMA COUNTY...AND SOUTHWEST PINAL COUNTY. THE
COMBINATION OF STRONG AND GUSTY SOUTHWEST WINDS...VERY LOW RELATIVE
HUMIDITIES...AND A HIGH TO VERY HIGH FIRE DANGER RATING WILL PRODUCE
CRITICAL FIRE WEATHER CONDITIONS. LESS WIND WILL OCCUR ON
SATURDAY...ALTHOUGH BREEZY WESTERLY WINDS SATURDAY AFTERNOON MAY
OCCUR NEAR THE NEW MEXICO BORDER.
THEREAFTER...MAINLY MID-LEVEL MOISTURE IS EXPECTED TO INCREASE
ACROSS GREENLEE...GRAHAM AND COCHISE COUNTIES EAST OF TUCSON BY
MONDAY. ALTHOUGH MEASURABLE RAINFALL IS EXPECTED TO REMAIN EAST OF
SOUTHEAST ARIZONA...DRY LIGHTNING MAY OCCUR MONDAY AFTERNOON AND
MONDAY EVENING MAINLY NEAR THE NEW MEXICO BORDER. BREEZY TO LOCALLY
WINDY CONDITIONS ARE FORECAST TO OCCUR TUESDAY AS ANOTHER TROUGH
MOVES EAST ACROSS THE AREA.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 11 AM TO 8 PM MST FRIDAY FOR AZZ146-148
(EXCEPT WESTERN AND CENTRAL PIMA COUNTY...AND SOUTHWEST PINAL
COUNTY).
$$
WEATHER.GOV/TUCSON
NWS TWC Office Area Forecast Discussion
