Drought in Utah, October 1 to 31, 2002

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
220 PM MDT MON SEP 30 2002

MESOETA INITIALIZED WELL OVER INTERMOUNTAIN WEST...AS DID OTHER
MAINLINE MODELS. FRONTAL BAND OVER NRN UT MOVING SLOWLY EAST AS SEEN
ON SATELLITE. MESOETA HALTS EASTERLY MOVEMENT LATE THIS AFTERNOON AND
BRINGS IT TO REST OVER NE UT AND XTRM NW CO. PATCHY CLOUDS AHEAD OF
THIS FRONT ALREADY SHEARING ACROSS NORTHERN THIRD OF THE CWA THIS
MORNING AND AFTERNOON. MODELS THEN STRENGTHEN AND DIG A STRONG TROUGH
INTO THE PACNW TUE AND WED. CLOSED LOW ENDS UP OVER SRN NEVADA WED
AFTERNOON...WITH FRONTAL ZONE CURRENTLY OVER NE UT/NWCO GETTING
CAUGHT UNDER THE DEFORMATION ZONE THAT DEVELOPS BETWEEN THE FLOW
AROUND THE CLOSED LOW AND THE WESTERLIES OVER THE NORTHERN ROCKIES.
SO THAT FRONT DOESNT MAKE MUCH PROGRESS SOUTH OR EAST AFTER THIS
AFTERNOON. MODELS HAVE CONSENSUS ON THIS. CURRENT SATELLITE HELPS
CONFIRM THIS...AS INITIAL TROUGH APPEARS TO BE DIGGING OFF THE WEST
COAST EVEN MORE THE SHORTRANGE MODELS PREDICTED THIS MORNING. THIS
SHOULD HELP THE NEXT IMPULSE...WHICH DIGS OUT THE STRONGER TROUGH AND
CLOSED LOW TO DIG EVEN MORE THAN 12Z MODELS EXPECT...THUS PRODUCING
EVEN LESS EASTERLY MOVEMENT. THIS SHOULD KEEP THE FRONTAL
ZONE/DEFORMATION ZONE STUCK ALONG THE CO/UT-WY BORDER THROUGH 24
HOURS.

AS CLOSED 500 MB LOWS MOVES INTO SRN NV FRONTAL ZONE IS DRAGGED SOUTH
SO SOME COOLING SHOULD OCCUR WED. EXPECT STRONGER SW WINDS TUE AND
WED AS JET MOVES OVERHEAD. MODELS SLOW EASTWARD PROGRESSION OF
THE WEATHER ASSOCIATED WITH THIS SYSTEM SO PUSHED IT BACK ABOUT
ONE PERIOD. WED COULD BE INTERESTING WITH GOOD DIVERGENT FLOW ALOFT
OVER THE AREA. MAIN FOCUS OF CONVECTIVE ACTIVITY SHOULD BE OVER NE
UT/NW CO. THUR COULD BE ANOTHER INTERESTING DAY AS AVN HAS A TROP
UNDULATION DOWN TO 700 MB.  CUOCO

EXTENDED PERIOD...FRIDAY THROUGH MONDAY...MRF AND EC DIVERGE
SIGNIFICANTLY ON SOLUTIONS.  EC HAS RECENTLY TENDED TO SPLIT THE
FLOW AT OUR LATITUDE IN EXTENDED PERIODS...WHILE MRF HAS PERSISTED
IN A CONSOLIDATED PROGRESSIVE FLOW.  WE ARE NOW INTO THAT TIME OF
YEAR WHEN THE FLOW AT MID LATITUDES TENDS TO BE MORE PROGRESSIVE
AND CONSOLIDATED...ESPECIALLY WHEN THE LONG WAVE TROF POSITION IS
OVER THE AREA OF CONCERN.  SINCE THIS IS THE APPARENT SITUATION FOR
THE EXTENDED PERIOD...WILL FOLLOW THE MRF GUIDANCE. SO FRI SHOULD
BE AN IN BETWEEN STORMS DAY. THEN A SHORT WAVE TROF SHOULD PHASE
WITH THE LONG WAVE TROF ON SATURDAY OVER OUR AREA FOR ANOTHER
UNSETTLED WX DAY.

APPEARS THAT LONG WAVE ANCHOR FOR LONG WAVE TROF OVER WESTERN NORTH
AMERICA WILL BE READJUSTING ITS POSITION SLIGHTLY FURTHER EAST
BEGINNING NEXT WEEK...WHICH IS NOT UNREASONABLE.  THAT BEING THE
CASE...HAVE SOME CONFIDENCE IN THE MRF TAKING THE STORM TRACK A
LITTLE FURTHER EAST AND LEAVING OUR CWFA UNDER A DRIER NW FLOW
ALOFT DURING THE FIRST PART OF NEXT WEEK. THIS WILL ALLOW MAX TEMPS
THROUGHOUT OUR CWFA TO RISE TO NEAR OR JUST A LITTLE BELOW NORMAL...
THOUGH MIN TEMPS LIKELY TO REMAIN AROUND 5 DEGREES BELOW NORMAL.
PRINGLE

.GJT...NONE.