Friday, July 22, 2005

Phoenix In Sight

Emily moisture front is now just reaching Phoenix. Emily-related clouds should now just begin to poke up past the Superstitions. The Phoenix dewpoint is still dropping...the moisture hasn't reached the surface yet. Now, I just hope the clouds don't SUPPRESS rain cloud development - something that made the 1987 monsoon such a bummer.

Here's the latest National Weather Service Weather Roundup forecast....

AREA FORECAST DISCUSSION, NATIONAL WEATHER SERVICE PHOENIX AZ, 315 AM MST FRI JUL 22 2005

SOUTHWEST AND SOUTH-CENTRAL ARIZONA...AND SOUTHEAST CALIFORNIA FORECAST DISCUSSION

.SYNOPSIS...
THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL INCREASE TONIGHT THROUGH THE WEEKEND AS TROPICAL MOISTURE FROM THE SOUTHEAST INCREASES. STRONG GUSTY WINDS ARE EXPECTED WITH SOME STORMS ALONG WITH DESERT DUST STORMS. THE POSSIBILITY OF HEAVY RAIN WILL INCREASE ESPECIALLY TONIGHT AND THIS WEEKEND AS ABUNDANT TROPICAL MOISTURE ASSOCIATED WITH THE REMAINS OF FORMER HURRICANE EMILY MOVES INTO ARIZONA AND SOUTHERN CALIFORNIA. LOWER TEMPERATURES AND HIGHER HUMIDITY ARE ALSO ANTICIPATED OVER THE WEEKEND.

.DISCUSSION...
UPPER HIGH PRESSURE WILL REMAIN CENTERED OVER CO / CENTRAL PLAINS AREAS INTO THE WEEKEND KEEPING A E-SE FLOW ACROSS OUR REGION. THIS FLOW WILL TAP INTO LOW LEVEL TROPICAL MOISTURE FROM THE REMAINS OF EMILY MOVING ACROSS MEXICO...AND BEGIN TO BRING IT INTO AND ACROSS SOUTHERN AZ / SE CA FRI NIGHT THROUGH THE WEEKEND. MODELS STILL SHOW GOOD INVERTED TROF EXTENDING NORTH FROM THE REMAINS OF EMILY WHICH WILL ENTER AND MOVE W ACROSS SOUTHERN AZ/SE CA ALSO ON FRI NIGHT AND THROUGH WEEKEND AS THE REMAINS OF EMILY MOVES ACROSS CENTRAL BAJA SAT. AN AREA OF DIVERGENCE ALOFT IS AND WILL CONTINUE TO EXIST OVER SOUTH CENTRAL AND SW AZ INTO THE WEEKEND. THIS WILL ALL RESULT IN AN INCREASING CHANCE OF THUNDERSTORMS OVER OUR REGION. THUNDERSTORMS FRI WILL GIVE STRONG GUSTY WINDS AS FORECAST SOUNDINGS SHOW GOOD INVERTED V. THE INVERTED V BECOMES A LITTLE LESS THROUGH THE WEEKEND AS THE LOW LEVEL MOISTURE INCREASES. AND BY FRI NIGHT OVER SW AZ SE CA AND BY SAT OVER SOUTH CENTRAL AZ P WATER VALUES REACH 2 INCHES... WITH SW AZ SE CA REACHING 2.2 INCHES AS MUCH OF THE LOW LEVEL MOISTURE THRUST SHIFTS TO THAT AREA. THIS WILL RESULT IN SOME THUNDERSTORMS PRODUCING LOCALLY HEAVY RAINFALL FRI THRU THE WEEKEND OUR REGION. THIS INCREASE IN MOISTURE WILL ALSO CAUSE TEMPS TO LOWER OVER THE WEEKEND. BY SUN THE INVERTED TROF IS MOVING W OFF THE COAST. BUT THE AIRMASS OVER OUR REGION WILL REMAIN MOIST SO WITH AFTERNOON HEATING...MAINLY AFTERNOON /EVENING THUNDERSTORMS WILL STILL DEVELOP...ALTHOUGH THEIR CHANCES WILL BE REDUCED ESPECIALLY OVER SE CA AND SW AZ. P-WATER VALUES ALSO GRADUALLY DECREASES THE FIRST PART OF NEXT WEEK SO BY TUES/WED THEY ARE DOWN TO AROUND 1.5 INCHES. ALSO...A HIGH PRESSURE CENTER WILL LOCATE ITSELF DURING THE FIRST PART OF NEXT WEEK OVER SOUTHERN NV / NORTHERN AZ. THIS WILL BRING A NE FLOW TO OUR REGION WHICH WILL HELP STEER THUNDERSTORMS FROM THE RIM TOWARD THE SOUTH CENTRAL AZ DESERT AREAS INCLUDING THE PHX AREA.

.AVIATION...
DISCUSSION FOR 12Z TAFS. SUFFICIENT MOISTURE AND INSTABILITY OVER THE AREA WILL LEAD TO A CHANCE OF SHOWERS AND THUNDERSTORMS AGAIN THIS AFTERNOON AND EVENING. THE CHANCE OF A THUNDERSTORM OVER KPHX/KIWA IS ABOUT 40 PERCENT WITH BLOWING DUST AND SHARPLY REDUCED VISIBILITY MORE LIKELY. THUNDERSTORM CHANCES AT KYUM... KBLH...AND KIPL WILL BE ABOUT 10 TO 20 PERCENT. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

.PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE.

DKS/MAF

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