River Flood Warning 26, NWS Grand Forks, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
254 PM CDT MON OCT 13 2008

.SHORT TERM...MAIN CONCERN THROUGH THURSDAY WILL BE MIN TEMPS AND
FROST/FREEZE HEADLINES. 12Z NAM APPEARS TO HAVE INITIALIZED 500MB
LOW BEST ACROSS W ND...WILL FOLLOW FOR THE NEAR TERM. MODELS IN
GENERAL AGREEMENT THROUGH THE PERIOD...BUT THERE ARE TIMING
DIFFERENCES WITH FAST MOVING WAVES. WILL USE A BLEND PAST TONIGHT.

UPPER LOW WILL CONTINUE TO PROPAGATE NE...THERE MAY BE AN ISOLD
SHOWER ACROSS THE N FA THIS EVENING AS THIS FEATURE MOVES BY.
ANTICIPATE MOSTLY CLEAR SKIES FOR A GOOD PORTION OF TONIGHT ONCE
UPPER LOW MOVES FAR ENOUGH AWAY. SFC HIGH WILL BE CENTERED ACROSS
THE CENTRAL PLAINS...WITH AXIS INTO THE N PLAINS. EXPECT WEAK SFC
PRESSURE GRADIENT AND WINDS PROBABLY WILL NOT BE TOTALLY CALM.
ALSO...EXPECT WEAK WARM AIR ADVECTION THROUGH THE NIGHT.
HOWEVER...WIND SHOULD BE LIGHT (@5KNTS) AFT 06Z GIVEN SYNOPTIC
SET-UP AND ALLOW TEMPS TO DROP NEAR DEW POINT VALUES (GIVEN WEAK
WINDS...WARM AIR ADVECTION ALOFT SHOULD HAVE MINIMAL AFFECT ON SFC
TEMPS). LOWEST DEW POINT VALUES EXPECTED TO BE ACROSS THE W
FA...AND 20Z TEMPS ONLY IN THE MID-UPPER 30S HERE. THUS...TEMPS
SHOULD BE ABLE TO DROP AOB 30F AND WILL ISSUE FREEZE WARNING THIS
LOCATION. WILL ISSUE FROST ADVISORY EAST OF THIS LOCATION (WHERE
NO HARD FREEZE HAS OCCURRED YET) AS DEW POINT TEMPS SHOULD REMAIN
A BIT HIGHER AND CURRENT TEMPS IN THE LOW-MID 40S. EVENING SHIFT
WILL NEED TO MONITOR CONDITIONS AND ADJUST HEADLINES AS NEEDED.

UPPER FLOW WILL BE MAINLY ZONAL THE REMAINDER OF THE PERIOD WITH
FAST MOVING WAVES. ONE SUCH SYSTEM WILL TRACK ACROSS S CANADA WITH
SFC TROUGH/COLD FRONT MOVING THROUGH THE FA TUE NIGHT. MAIN
FORCING N OF THE INTERNATIONAL BORDER SO FROPA SHOULD BE DRY.
TEMPS WILL BE NEAR NORMAL ON TUE AHEAD OF THE SYSTEM...THEN FALL
BACK BELOW NORMAL WED INTO THUR. NEXT CHANCE FOR HARD FREEZE WILL
BE THUR MORNING. THIS ACTUALLY LOOKS LIKE A FAIRLY DECENT CHANCE
WITH CALM WINDS AND 850MB TEMPS BELOW ZERO. NEXT UPPER WAVE
APPROACHES THE FA ON THUR AND WILL KEEP LOW END POPS ACROSS THE
FAR S FA.

.LONG TERM FRI-MON...PATTERN STILL LOOKS TO REMAIN ZONAL FOR
THE MOST PART...AND THE ECMWF AND ITS ENSEMBLE GET THE NOD FOR THE
LONG RANGE TODAY. WILL MAINLY TRY TO TIME THE MINOR SHORT WAVES IN
THE FLOW...WITH THE FIRST STILL OVER THE FA ON FRI. LOTS OF
DIFFERENCE BETWEEN THE CANADIAN/GFS/ECMWF OVER QPF WITH THIS
SYSTEM (ECMWF THE MOST ROBUST). HEIGHTS THEN BEGIN TO BUILD BACK
UP BEHIND THIS SYSTEM WITH THE NEXT WAVE SHOWING UP BY LATER SAT.
GFS AND ECMWF SHOW PRETTY GOOD CONSISTENCY DEPICTING A BAND OF
PCPN ALONG AND NORTH OF HIGHWAY 2. ONCE AGAIN...THE CANADIAN IS AN
OUTLIER WITH A DRY FORECAST. WILL LINGER SOME PCPN ASSOCIATED WITH
THIS SYSTEM FOR SAT NIGHT INTO SUNDAY.

&&

.AVIATION...TIMING OUT THE CLOUDS WILL BE THE AVIATION CHALLENGE
TONIGHT. AS THE 500MB LOW TRACKS TO THE NORTHEAST TONIGHT...IT
SHOULD DRAG THRU THE LAST BAND OF CLOUDS. THIS LOOKS TO BE
SOMETIME IN THE EVENING... WHICH SHOULD LEAVE VERY LITTLE CLOUD
COVER IN ITS WAKE. WIND SPEEDS NEVER LOOK TO GO COMPLETELY LIGHT
TONIGHT...BUT KFAR/KGFK COULD TAKE ON MORE OF A SOUTHWARD
COMPONENT TONIGHT THAN THE HIGHER ELEVATIONS TO THE EAST AND WEST.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FROST ADVISORY FROM 1 AM TO 9 AM CDT TUESDAY FOR NDZ008-016-027-
     029-030-039-053.

     FREEZE WARNING FROM 1 AM TO 9 AM CDT TUESDAY FOR NDZ006-007-014-
     015-024-026-028-038-049-052-054.

MN...FROST ADVISORY FROM 1 AM TO 9 AM CDT TUESDAY FOR MNZ001>005-007-
     008-013>016-022-023-027>031-040.

&&

TG/GODON