Severe Thunderstorm Warning 258, NWS Grand Forks, ND

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
325 PM CDT SAT SEP 2 2000

FORECAST PROBLEM FOR TONIGHT AND SUNDAY IS PCPN. LATEST VIS AND IR
SATELLITE IMAGERY SHOWS CWFA COVERED IN IFR DECK WITH COLDEST CLOUD
TOPS WORKING INTO S RRV. LATEST MSAS SFC PRESSURE ANALYSIS HAS LOW
CENTERED IN SE MT WITH TROF EXTENDING THROUGH W SD TO ANOTHER LOW IN
EXTREME NE NEBRASKA. CWFA REMAINS IN MOIST E-SE FLOW. CONVECTION
STILL FIRING ALONG 850MB WARM FRONT WHICH ACCORDING TO 12Z UA
ANALYSIS EXTENDING THROUGH SE ND INTO WC MN. KMVX HAS REMAINDER OF
PCPN EXTENDING NE FROM THESE TSRA INTO NW MN. WHEN COMPARING MSAS
PRESSURE ANALYSIS TO MODELS...ETA MATCHES BEST WITH AVN ALSO CLOSE.
THEREFORE...PRIMARILY UTILIZED ETA FOR FORECAST. MODELS KEEP PCPN
POTENTIAL OVER CWFA AS JET CONTINUES TO PUNCH N INTO ND AND SFC
INSTABILITY PARAMETERS CONTINUE TO DESTABILIZE 00Z. THEREFORE...
EXPECT TSRA TO CONTINUE THIS EVENING...WITH ISOLD SVR AS
WELL...ESPECIALLY IN S CWFA. BEST INSTABILITY SHIFTS INTO MN
OVERNIGHT...WITH LINGERING PCPN POTENTIAL IN THE MORNING FOR MN SIDE
OF CWFA. WILL NEED TO KEEP URBAN AND SMALL STREAM FLOOD ADVISORY
OUT FOR SE ND AND EXTEND IT INTO PART OF WC MN...AS LINE OF HEAVIEST
CONVECTION SLOWLY MOVING E AND NE...INCLUDING THE FARGO/MOORHEAD
AREA.

FORECAST PROBLEM FOR THIRD AND FOURTH PERIODS IS TEMPS. WITH
EASTERLY FLOW CONTINUING...WITH NO STRONG COLD FRONT ANTICIPATED TO
SCOUR OUT THE LOW LEVEL MOISTURE...CAN EXPECT MO CLDY SKY AND COOLER
TEMPS TO REMAIN. THEREFORE...KEPT TEMPS IN THE NORMAL TO SLIGHTLY
BELOW NORMAL RANGE.

EXTENDED...INITIALLY MODELS IN FAIR AGREEMENT WITH RIDGE AXIS
SHIFTING INTO MN PUTTING FA IN SW FLOW ALOFT THROUGH FIRST HALF OF
WORK WEEK. MODELS THEN DIVERGE. UK INITIALLY IN AGREEMENT WITH OTHER
MODELS...THEN RETROGRESSES BROAD UPPER RIDGE AXIS BACK OVR N CENTRAL
STATES WHICH SEEMS INCONSISTENT. OTHERWISE...TREND IS TO TRACK
TROF THROUGH FA WITH MRF SLOWEST BETWEEN CAN/EURO AND NOGAPS.
THEN...THE RELATIVELY STATIONARY HIGH PLAINS SFC LOW BEGINS TO PUSH
EAST...AND WITH THE SW FLOW EJECTING ENERGY NE...WILL CONTINUE
MENTION OF PCPN DURING THIS TIME FRAME. WITH PASSAGE OF TROF AND
APPROACH OF SFC HIGH...WILL CARRY DRY FCST INTO SATURDAY.
THICKNESS AND H8 TEMPS INDICATE SEASONAL TEMPS INTO MIDWEEK...THEN A
COOLDOWN FOLLOWING CFP AFT >THURSDAY.

.FGF...NONE

NG/VOELKER