872 
FXUS63 KUNR 291018
AFDRAP
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
330 AM MDT SUN APR 29 2001

LATEST SFC ANALYSIS PLACES MAIN LOW WELL INTO SRN CANADA WITH COLD 
FRONT EXTENDING S ALONG THE MT/ND BORDER AND BACK INTO NRN WY. 
SATELLITE INDC SCT CLOUDS OVER CWFA AND ANOTHER BROAD AREAS OF 
DEVELOPING CLOUDS OVER CENTRAL WY ASSOC WITH UPPER LEVEL DYNAMICS. 
KUDX PICKING UP A COUPLE SHOWERS OUTSIDE OF CWFA. 

MODELS INITIALIZE O.K. WITH MAIN FEATURES AND SHOW PRETTY GOOD 
AGREEMENT. ETA CONTINUES TO INITIALIZE AND MAINTAIN TOO MUCH LOW 
LEVEL MOISTURE OVER WRN DAKOTAS. SFC DEWPOINTS INITIALIZED 10-15 
DEGREES F TOO HIGH. THIS HAS RAMIFICATIONS IN CAPE AND STABILITY 
PARAMETERS FROM THE ETA. STEEP LAPSE RATES WILL BE AROUND TODAY 
COMBINED WITH GOOD DYNAMICS...TO PRODUCE SOME SHOWER 
ACTIVITY...ESPECIALLY IN CENTRAL SD ZONES. COLD FRONT WILL MOVE 
ACROSS CWFA TODAY. GOOD FRONTOGENESIS AND DYNAMIC FORCING THROUGH 
THE DAY IS EXPECTED. MOISTURE IS SOMEWHAT LIMITED. WILL EXPECT LOW 
CHANCE OR ISOLD SHOWERS AND TSTM OVER CWFA. VERY DRY LOW LEVELS WILL 
ALLOW SIGNIFICANT EVAPORATIVE PROCESSES WHERE PRECIP DOES DEVELOP. 
AS THIS SYSTEM MOVES THROUGH TODAY...SFC HIGH PRESSURE BUILDS OVER 
NRN PLAINS. UPPER FLOW BECOMES ZONAL OVER THE NW U.S. WHICH WILL 
SEND A SERIES OF WEAK S/WVS ACROSS NRN U.S. THROUGH MID WEEK. LITTLE 
TEMPERATURE CHANGE EXPECTED FROM DAY TO DAY AND PRECIP WILL DEPEND 
UPON MOISTURE AVAILABILITY. FIRST IN SERIES OF WAVES BEGINS LATE 
MONDAY AND WILL SEE A NEARLY DAILY CHANCE (LOW CHANCE) OF PRECIP 
THROUGH THE EXTENDED PERIODS. 

GUIDANCE TEMPS LOOK GOOD AND HAVE NOT STRAYED TOO MUCH. POPS A 
LITTLE LOW...HAVE TWEAKED THEM JUST A BIT. 

.UNR...NONE.

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