weather.gov     
National Weather Service

Area Forecast Discussion
NWS Homepage
This page is being discontinued on March 12, 2014.
The same data is available at this site. Please update your bookmarks.
Thank you, and we apologize for the inconvenience.
Please send an email to SR-SRH.Webmaster@noaa.gov with any concerns.


Current Version
Previous Version:    01  02  03  04  05  06  07  08  09  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  
[Printable]
733
FXUS65 KTWC 010947
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
245 AM MST FRI AUG 1 2014

.SYNOPSIS...PLENTY OF SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY
THROUGH SATURDAY NIGHT THANKS TO AN INCREASE IN MOISTURE AND A
PASSING UPPER LEVEL DISTURBANCE.  WITH THE ABUNDANT MOISTURE THAT
WILL BE PRESENT...LOCALLY HEAVY RAINFALL IS A POSSIBILITY WITH
STRONGER OR SLOWER MOVING STORMS...PRIMARILY DURING THE AFTERNOON
AND EVENING HOURS.  DIMINISHING MONSOONAL MOISTURE EARLY NEXT WEEK
WILL RESULT IN LESS CONVECTION FROM MONDAY ONWARD.

&&

.DISCUSSION...PLENTY OF SHOWERS WITH ISOLATED THUNDERSTORMS ACROSS
MUCH OF THE AREA EARLY THIS MORNING AS WAS SUGGESTED BY LAST NIGHTS
MESOSCALE MODELS.  GENERAL ANTICYCLONIC MOTION TO THE ENTIRE FIELD
WITH MANY INDIVIDUAL STORMS DISPLAYING VERY DEVIANT MOTION DUE TO
OUTFLOW BOUNDARIES.  I EXPECT THE CONVECTION WILL CONTINUE FOR
SEVERAL MORE HOURS BEFORE WINDING DOWN NEAR AND SHORTLY AFTER
SUN-UP.  THEN WITH ABUNDANT ATMOSPHERIC MOISTURE AND A MID LEVEL
FEATURE SLOWLY APPROACHING FROM THE SOUTH...EXPECTING PLENTY OF
CONVECTION TO FIRE UP AGAIN THIS AFTERNOON...CONTINUING THROUGH THE
EVENING.  OVERALL THE STORMS WILL BE FAIRLY SLOW MOVING AND RATHER
EFFICIENT RAINFALL PRODUCERS SO WILL NEED TO KEEP AN EYE OUT FOR
POTENTIAL LOCAL FLOODING PROBLEMS.  EARLIER THERE WAS CONCERN FOR
BLOWING DUST PROBLEMS THIS AFTERNOON NW OF TUCSON UP I-10 BUT DO TO
THE PLENTIFUL SHOWER ACTIVITY THIS AREA LAST COUPLE OF HOURS THAT
THREAT IS LESSENED SO HAVE TWEAKED GRIDS FROM AREAS OF DUST TO
PATCHY DUST.

WITH THE MID LEVEL FEATURE IN THE AREA TONIGHT WOULD EXPECT ANOTHER
ACTIVE NIGHT CONVECTION WISE.  FOR SATURDAY...THE GFS/ECMWF PAIR
MOVE THIS MID LEVEL FEATURE NORTH SLOWER THAN THE NAM DOES.  THE NAM
WOULD SHIFT THE FOCUS OUT OF THE AREA EARLY WITH LESS CONVECTION
SATURDAY.  THE GFS/ECMWF BEING SLOWER WOULD ALLOW FOR MORE ABUNDANT
CONVECTION SATURDAY AFTERNOON AND EVENING.  AT THIS TIME PREFER THE
SLOWER SOLUTION WITH THIS TYPE OF SYSTEM WHICH IS BASICALLY WHAT WE
HAVE BEEN RUNNING WITH AND IS WELL COORDINATED WITH SURROUNDING
OFFICES.  IF THIS ALL PANS OUT THIS WOULD ALSO BE THE TIME PERIOD OF
MOST CONCERN FOR LOCAL HEAVY RAINFALL PRODUCING RUNOFF PROBLEMS.
WILL NEED TO BE WATCHED.  ALL THIS CONVECTION TODAY AND SATURDAY
WILL BE ENOUGH TO HOLD AFTERNOON TEMPERATURES SEVERAL DEGREES BELOW
NORMAL AS WELL.

BY SUNDAY THIS SYSTEM SHOULD HAVE SHIFTED FAR ENOUGH NORTH TO NO
LONGER BE FORCING OUR CONVECTION...HOWEVER MOISTURE LEFT BEHIND
SHOULD ALLOW FOR SOME AFTERNOON THUNDERSTORMS TO DEVELOP.  THIS
WOULD LIKELY BE THE EASTERN TWO THIRDS OF THE AREA AS DRIER AIR IS
BEGINNING TO WORK IN FROM THE SW IN THE WAKE OF THE DEPARTING
SYSTEM.

BEYOND THAT...MONDAY AND TUESDAY STILL HAVE ENOUGH MOISTURE OVER
EASTERN AREAS TO ALLOW FOR SOME AFTERNOON/EVENING CONVECTION...WITH
LESS TUESDAY COMPARED TO MONDAY.  AFTERNOON TEMPERATURES WARMING AS
WELL WITH HIGHS BACK UP TO NORMAL LEVELS.

LATER IN THE WEEK...SW FLOW DEVELOPS ACROSS THE AREA AS AN UPPER
LEVEL TROUGH DIGS INTO THE WEST COAST.  THIS WILL REDUCE THE
MONSOONAL MOISTURE ACROSS THE REGION WITH A RESULTANT DECREASE IN
CONVECTION.  AT THIS POINT IT LOOKS AS THOUGH CONVECTION WILL BE
LIMITED TO THE NEW MEXICO BORDER AREA.  CERNIGLIA

&&

.AVIATION...VALID THRU 02/06Z.
ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THE EARLY
MORNING HOURS. STORMS MAY IMPACT TERMINALS...WITH KDUG HAVING THE
HIGHEST CHANCE DURING THE NEXT 3 HOURS. A BRIEF RESPITE FROM THE
SHOWERS AND STORMS SHOULD OCCUR DURING THE PREDAWN HOURS AND INTO
THE MORNING AFTER SUNRISE WITH ONLY ISOLATED SHOWERS AND
THUNDERSTORMS EXPECTED. HOWEVER...SCATTERED TO LOCALLY NUMEROUS
SHOWERS/THUNDERSTORMS WILL DEVELOP ONCE AGAIN DURING THE LATE
MORNING AND EARLY AFTERNOON WITH THE POTENTIAL FOR HEAVY RAIN AND
GUSTY WINDS...WITH THE THREAT FOR SHOWERS AND THUNDERSTORMS
CONTINUING INTO THE EVENING HOURS. EXPECT LOWERING OF CIGS AND
REDUCED VSBYS NEAR THUNDERSTORMS...WITH MVFR CONDITIONS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...SHOWER AND THUNDERSTORM ACTIVITY WILL BE ON THE
INCREASE THROUGH THE NEXT 48 TO 72 HOURS AS MONSOON MOISTURE SURGES
IN FROM THE SOUTH. EXPECT STRONG...GUSTY AND ERRATIC WINDS WITH THE
STRONGER THUNDERSTORMS. INCREASING MOISTURE WILL ALSO TRANSLATE INTO
PERIODS OF HEAVY RAINFALL AND COOLER TEMPERATURES THIS WEEKEND...
PARTICULARLY SATURDAY. THEREAFTER...A DRYING TREND WITH WARMER
TEMPERATURES WILL PREVAIL BY THE MIDDLE OF NEXT WEEK.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON








U.S. Dept. of Commerce
NOAA National Weather Service
1325 East West Highway
Silver Spring, MD 20910
E-mail: w-nws.webmaster@noaa.gov
Page last modified: May 16, 2007
NATIONAL WEATHER SERVICE: for Safety, for Work, for Fun - FOR LIFE