422
FXUS65 KTWC 060912
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
212 AM MST TUE MAY 6 2025
SYNOPSIS
A SLOW-MOVING WEATHER SYSTEM WILL BRING COOLER TEMPERATURES
WITH PERIODIC CHANCES FOR SCATTERED SHOWERS TODAY AND WEDNESDAY.
TEMPERATURES WILL THEN REBOUND THE SECOND HALF OF THE WEEK, WITH
THE POSSIBILITY FOR REACHING THE CENTURY MARK IN THE TUCSON METRO
AREA NEXT WEEKEND.
DISCUSSION
THE UPPER PATTERN THIS MORNING IS DEFINED BY A MEAN
TROUGH ACROSS THE INTERMOUNTAIN WEST, WITH A STRONG UPPER-LOW
WITHIN THE TROUGH ALONG THE ARIZONA AND NEW MEXICO BORDER AND
ANOTHER STRONG VORT-LOBE ROTATING SOUTH ALONG THE BACKSIDE OF THE
TROUGH IN NORTHEAST NEVADA. THE LATEST RADAR IMAGERY INDICATED A
FEW LIGHT SHOWERS MOVING SOUTHEAST ACROSS SOUTHERN MARICOPA AND
WESTERN PIMA COUNTY. THESE SHOWERS ARE ASSOCIATED WITH A VORT MAX
MOVING ALONG THE SOUTHERN PERIPHERY OF THE UPPER-LOW. AS WE MOVE
THROUGH THE DAY TODAY, WE WILL SEE THIS FEATURE MOVE EAST AND
BEGIN TO ELONGATE THE UPPER-LOW INTO AN E-W ORIENTATION ACROSS
NRN NM WHILE THE OTHER VORT-LOBE IN THE MEAN TROUGH IN NE NV MOVES
SOUTH INTO SRN NV. THIS WILL CREATE A DEFORMATION AXIS BETWEEN
THE TWO FEATURES THAT WILL SAG SOUTH ACROSS THE NORTHERN PORTIONS
OF OUR CWA TODAY, ASSISTING SHOWER DEVELOPMENT ACROSS SE
PINAL/GRAHAM AND GREENLEE COUNTIES THIS AFTERNOON AND EVENING.
THESE SHOWERS WILL GENERALLY BE LIGHT IN NATURE (BETWEEN 0.10-0.25
INCHES WITH A FEW LOCALIZED AREAS NEAR THE WHITE MOUNTAINS UP TO
0.50 INCHES). THIS ACTIVITY WILL BE QUICKLY BE SHUT DOWN THIS
EVENING WITH DECENT SUBSIDENCE DUE TO THE DEPARTING UPPER-LOW.
THE SECOND FEATURE MAKES ITS WAY INTO SW AZ BY 07/18Z THEN
SHEARS-OUT IN THE MID-LEVELS WITH A WEAK BOUNDARY TRACKING ACROSS
SOUTHEAST ARIZONA WEDNESDAY AFTERNOON. GIVEN THE MOISTURE IN PLACE
ACROSS THE AREA, WE WILL SEE ANOTHER ROUND OF WEAK SHOWERS MOVE
THROUGH THE AREA WEDNESDAY AFTERNOON. RAINFALL AMOUNTS WITH THIS
SECOND FEATURE WILL GENERALLY BE 0.01-0.10 INCHES. IN ANY EVENT,
ALTHOUGH WE WILL EXPERIENCE SCATTERED LIGHT SHOWERS MOVING ACROSS
SOUTHEAST ARIZONA THE NEXT FEW DAYS, NEITHER SYSTEM IS EXPECTED TO
BE IMPACTFUL.
AS WE MOVE INTO THE SECOND HALF OF THE WEEK, WE WILL SEE A RIDGE
OF HIGH PRESSURE BUILD INTO THE DESERT SOUTHWEST. EXPECT AFTERNOON
TEMPERATURES ACROSS THE OLD PUEBLO TO WARM BACK-UP RAPIDLY (WITH
7-10 DEGREES OF WARMING WEDNESDAY, THURSDAY AND FRIDAY...NEARING
THE CENTURY MARK NEXT WEEKEND. THE NBM PROBABILITIES (06/05Z) FOR
MEETING OR EXCEEDING 100 DEGREES AT THE TUCSON INTERNATIONAL
AIRPORT (KTUS) ARE 12% FRIDAY/42% SATURDAY/57% SUNDAY.
AVIATION
VALID THROUGH 07/12Z. WIDESPREAD CUMULUS AT 7K-10K
FEET AGL WITH OCCASIONAL PERIODS OF LOWER CLOUD DECKS AT 4K-7K FT
AGL WITH SCT -SHRA. MOUNTAIN OBSCURATIONS WITH LOWER VISIBILITIES
LIKELY WITH THESE LOWER CLOUDS AND SHOWERS. SFC WINDS LIGHT (LESS
THAN 10 KTS) AND TERRAIN DRIVEN THROUGH 06/18Z...THEN W-NW 10-15
KTS WITH GUSTS TO 25 MPH. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
FIRE WEATHER
ISOLATED TO SCATTERED SHOWERS WILL CONTINUE
THROUGH WEDNESDAY WITH UNSEASONABLY COOL TEMPERATURES AND MINIMUM
RELATIVE HUMIDITIES ABOVE 25 PERCENT. A WARMING AND DRYING TREND IS
EXPECTED FOR THE SECOND HALF OF THE WEEK WITH MINIMUM HUMIDITIES
RETURNING TO THE SINGE DIGITS. BREEZY SOUTHEAST WINDS WILL IMPACT
AREAS EAST OF TUCSON AS EARLY AS FRIDAY, BUT ESPECIALLY SATURDAY
AND SUNDAY.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
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