Severe Thunderstorm Warning 159, NWS Aberdeen, SD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
355 AM CDT SAT JUL 23 2005

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
STRONG CONVECTION GOING EARLY THIS MRNG IN SC ND ON THE NOSE OF THE
LLJ WITH VERY WARM MID LEVEL TEMPS. ALSO...SOME CONVECTION IN NC SD.
EXPECT THIS CONVECTION TO CONTINUE TO MOVE EAST THROUGH THE MORNING
HOURS. OTHERWISE...IT SHOULD BE A HOT DAY ACROSS THE CWA AS VERY
WARM LL TEMPS ADVECT INTO THE AREA FROM THE SW. WITH DWPTS IN THE
LOW TO MID 70S AND TEMPS WARMING UP...HEAT INDICES SHOULD REACH 105
OR GREATER THIS AFTN AND EARLY EVENING IN C AND NE SD AND WC MN. THE
DWPTS WILL BE FALLING THIS AFTN IN C SD AS WINDS BECOME SW AND W BUT
THE TEMPS WILL CONTINUE TO RISE TO AROUND 105. THUS...WILL GO WITH A
HEAT ADVISORY FOR MUCH OF THE CWA FOR THIS AFTN AND EARLY EVENING.
IT SHOULD BE LESS HUMID AND COOLER ON SUNDAY WITH THE AREA STILL
CAPPED FOR CONVECTION. THE MDLS AGREE REALLY WELL THAT A S/W WILL BE
AFFECTING THE CWA SUNDAY NIGHT THROUGH MONDAY NIGHT WITH A DECENT
COLD FRONT MOVING THROUGH. THE MDLS ALSO SHOW THE MID LEVELS COOLING
OFF ALONG WITH SOME QPF FOR SUN NIGHT THROUGH MON NIGHT. STAYED WITH
THE 30 POPS FOR TSRAS ACROSS THE CWA FOR THIS TIME PERIOD WITH 40
POPS ALONG THE S CWA. MONDAY SHOULD AGAIN BE COOLER THAN SUNDAY WITH
HIGHS MOSTLY IN THE 80S.

.LONG TERM...TUESDAY THROUGH FRIDAY
MODELS IN GOOD AGREEMENT FOR THE START OF EXTENDED PERIOD. SURFACE
HIGH PRESSURE AND DRIER AIRMASS LOOK TO BUILD INTO THE REGION IN
THE WAKE OF DEPARTING SHORT WAVE TROUGH. COLD AIR ADVECTION WILL
KEEP TEMPERATURES BELOW NORMAL FOR TUESDAY AND WEDNESDAY AS H85
TEMPERATURES FALL TO THE LOW TO MID TEENS CELSIUS. CWA REMAINS UNDER
ZONAL FLOW THROUGH THE REST OF THE EXTENDED WITH LOW LEVEL RETURN
FLOW AND WARM AIR ADVECTION BEGINNING WEDNESDAY NIGHT INTO THURSDAY
IN RESPONSE TO NEXT APPROACHING SHORT WAVE. UNCERTAINTY LIES IN THE
TIMING OF THIS NEXT TROUGH FEATURE HOWEVER. GFS IN FAIR AGREEMENT
WITH ECMWF IN BRINGING SURFACE TROUGH THROUGH FORECAST AREA ON
FRIDAY...WHILE DGEX BRINGS IT THROUGH ON THURSDAY. WITH H7 TEMPS OF
+10 TO +12C IN PLACE OVER CWA AND LOW CONFIDENCE IN THE TIMING OF
THE SYSTEM...DECIDED TO LEAVE EXTENDED GRIDS DRY AT THIS TIME.

&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...HEAT ADVISORY...NOON THROUGH 7 PM CDT...C AND NE SD
MN...HEAT ADVISORY...NOON THROUGH 7 PM CDT...BIG STONE AND TRAVERSE.
&&

MOHR/LILES