FXUS63 KDLH 172028
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
327 PM CDT SAT MAY 17 2003

FORECAST CONCERNS ARE ON PCPN CHANCES. SFC HIGH PRESSURE CONTINUES
ITS GRIP ON THE CWFA THIS AFTERNOON. DRY AIR FROM THE HIGH HAS BEEN
EFFICIENT AT ERODING THE LOW CLOUDS THAT HAVE BEEN TRYING TO MOVE
IN FROM THE W ALL DAY AND PRECLUDING ANY PCPN FROM REACHING THE
GROUND. INVERTED SFC TROF IN THE RED RIVER VALLEY REMAINS
STATIONARY.

A FAST MOVING PIECE OF SHORT WAVE ENERGY WILL RIDE UP ALONG THE
INVERTED TROF TONIGHT. -SHRA WILL STAY PRIMARILY TO THE W OF THE
FA...BUT A FEW MAY LEAK OVER INTO KOOCHICHING COUNTY IN THE
VICINITY OF SOME WEAK ISENTROPIC PRESSURE ADVECTION AND LOWEST
CONDENSATION PRESSURE DEFICITS ON 305K SFC. HAVE ADDED SPRINKLES TO
THE REMINDER OF THE FAR WESTERN TIER OF FA DUE TO CLOSE PROXIMITY
OF SHORT WAVE ENERGY.

INVERTED SFC TROF EXPECTED TO BECOME A COLD FRONT ON SUNDAY AND MOVE
INTO NW MN. BEST MOISTURE CONVERGENCE AND INSTABILITY TO BE
CONFINED TO THE FRONT. CONDENSATION PRESSURE DEFICITS RISE TO
GREATER THAN 50 MB IN THE WEST WITH EVEN HIGH VALUES FURTHER EAST.
WILL KEEP A POP IN KOOCHICHING COUNTY IN THE NW QUAD AND SPRINKLES
IN THE REST OF THE WESTERN TIER. DRY AIR WILL KEEP PCPN OUT OF
THE REST OF THE FA. CLOUD COVER WILL HOLD BACK TEMPS A BIT ON
SUNDAY.

SFC COLD FRONT FINALLY STARTS TO GET PUSHED FURTHER E SUNDAY NIGHT.
PCPN WILL SPREAD A BIT FARTHER EAST AND HAVE RESPONDED WITH POPS
AND MENTION OF -TSRA AND ATMOSPHERE DESTABILIZES ALONG AND JUST
AHEAD OF THE FRONT. -TSRA WILL BE ELEVATED IN NATURE AS H85 COMPUTED
LI'S APPROACH 0 C BY 12Z MONDAY.

COLD FRONT STRENGTHENS ON MONDAY AS UPPER LEVEL TROF COMES IN FROM
THE WEST WITH VERY COLD AIR ALOFT (-4 C AT H85). THE FRONT WILL
BENEFIT FROM DAYTIME HEATING IN THE EASTERN HALF OF THE FA TO
DESTABILIZE. BEST CHANCE FOR ORGANIZED CONVECTION WILL OCCUR ON
MONDAY AFTERNOON IN NW WI. SFC BASED LI'S FROM THE ETA DROP TO -4 C
AND SFC BASED CAPE'S RISING TO 1500 J/KG.  USED LIKELY POPS ON
MONDAY ALONG AND AHEAD OF THE FRONT...DIMINISHING TO SHOWERS AS THE
FRONT PASSE AND BECOMES MORE STABLE. WILL LINGER SOME -SHRA OVER
THE EASTERN FA MONDAY NIGHT...ENDING ALL PCPN CHANCES AFTER
MIDNIGHT AS HIGH PRESSURE BUILDS IN FROM THE WEST.

HIGH WILL PERSIST UNTIL WEDNESDAY WHEN THE NEXT UPPER LEVEL TROF
DROPS OUT OF THE CANADIAN PLAINS TOWARD THE INTERNATIONAL BORDER.
HAVE PLACED SMALL POPS OVER THE FA TO ACCOUNT FOR THIS FEATURE.

.DLH...NONE.

$$

GSF