Severe Thunderstorm Warning 128, NWS Aberdeen, SD

AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST
SOUTH DAKOTA AND WEST CENTRAL MINNESOTA
NATIONAL WEATHER SERVICE ABERDEEN SD
315 PM CDT SAT AUG 5 2000

MAIN CONCERN FOR TONIGHT WILL BE A SHORTWAVE DROPPING SOUTHEAST
ACROSS NORTH DAKOTA AND INTO SOUTH DAKOTA THIS EVENING. KBIS RADAR
AND LIGHTNING CHART INDICATED ACTIVITY WAS OCCURRING ACROSS
NORTHWEST NORTH DAKOTA AT THIS TIME AND WAS DROPPING SOUTHEAST
TOWARDS THE CWA. ETA/NGM/AVN MODELS ARE SIMILIAR WITH THE STRENGTH
OF THIS FEATURE. INTERESTING ENOUGH...ONLY THE (ETA!) IS DEPICTING
LIGHT RAINFALL AMOUNTS OVER THE CWA TONIGHT. THIS FEATURE IS
SIGNIFICANT ENOUGH TO WARRANT AT LEAST A SMALL POP TONIGHT AND DID
REINTRODUCE POPS OVER THE ENTIRE CWA WITH THE HIGHEST PERCENTAGES
OVER THE NORTHEAST. CAPE VALUES ON THE ETA ONLY CLIMB TO AROUND 1000
J/KG WITH WEAK WIND SHEAR. DO NOT EXPECT ANY OF THESE STORMS TO BE
SEVERE. THE OTHER CONCERN FOR TONIGHT WILL BE THE FOG...RAINFALL WAS
WIDESPREAD OVER MUCH OF THE CWA LAST TONIGHT. EXPECT THE SKY TO
CLEAR LATE TONIGHT ALONG WITH LIGHT NORTHWEST WINDS SHOULD ALLOW
SOME FOG FORMATION. HOWEVER...DRYER AIR IS ALSO MOVING INTO THE
WESTERN SECTIONS OF THE CWA...SO DID NOT MENTION DENSE FOG AT THIS
TIME. EVENING CREW WILL NEED TO MONITOR THIS. GUIDANCE TEMPERATURES
LOOK REASONABLE AND FOLLOWED.

FOR SUNDAY...ETA/NGM MODELS INDICATING SIGNIFICANT LOW LEVEL
MOISTURE AROUND 850MB ACROSS THE EAST DURING THE DAY. WILL GO PARTLY
SUNNY THERE WITH FORECAST TEMPERATURES NEAR GUIDANCE THERE. IN THE
WEST...WILL GO PARTLY CLOUDY AND GO AT OR SLIGHTLY ABOVE GUIDANCE
TEMPERATURES...ESPECIALLY IN PIERRE.

FOR SUNDAY NIGHT...A QUIET NIGHT IS IN STORE FOR THE REGION. A
MOSTLY CLEAR SKY AND LIGHT WINDS WILL ALLOW TEMPERATURES TO FALL
INTO THE 50S IN THE NORTHEAST TO AROUND 60 IN THE CENTRAL. THOUGHT
ABOUT FOG...BUT WITH DRYER AIR MASS MOVING IN...WILL LEAVE IT OUT
FOR NOW.

FOR MONDAY...SOUTHERLY WINDS RETURN ALONG WITH SLIGHTLY WARMER
TEMPERATURES. WILL ADD A SMALL POP IN THE WEST FOR LATE AFTERNOON
THUNDERSTORMS PER AVN MODEL. THINK THE BEST CHANCES FOR STORMS WILL
BE MONDAY NIGHT.

.EXTENDED FORECAST...
CANADIAN/NOGAPS/ECMWF SEEM TO BE IN BETTER AGREEMENT THAN THE MRF
WITH RERSPECT TO QPF DURING THE PERIOD. MRF IS KICKING OUT AN MCS
TUESDAY NIGHT INTO WEDNESDAY MORNING WHILE OTHER MODELS DO NOT SHOW
ANY PRECIPITATION. SINCE CURRENT FORECAST HAD THE CHANCE OF STORMS...
WILL LEAVE IT IN AND LET ANOTHER MODEL RUN RESOLVE THIS ISSUE THAN
FLIP FLOP FROM FORECAST TO FORECAST. OTHER CONCERNS DURING THIS
PERIOD...A FEW SHOWERS MAY LINGER INTO TUESDAY MORNING IN THE
WATERTOWN GROUP BUT WILL NOT MENTION IT AT THIS TIME. OTHERWISE
500MB RIDGE BUILDS OVER THE ROCKIES INTO THE CENTRAL UNITED STATES.
THE MRF HAS BEEN NOTORIOUSLY WARM BY SEVERAL DEGREES WITH 850MB
TEMPERATURES OVER THE LAST FEW WEEKS COMPARED TO THEc ECMWF AND
NOGAPS MODELS. EVEN WITH BUILDING RIDGE OVER US...WENT CONSERVATIVE
ON THE WARMUP THROUGH THE PERIOD.

.ABR...NONE.
ECKBERG