Heavy Snow in Michigan, April 17, 2001

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
315 AM EDT TUE APR 17 2001

NARROW BAND OF SNOW WAS MOVING SOUTH ACROSS THE SAGINAW VALLEY AND
NORTHERN THUMB EARLY THIS MORNING. VSBYS DOWN TO AROUND 2SM AT KBAX
BUT KDTX 88D SHOWS SOME HIGHER REFLECTIVITIES IN SMALLER SCALE
BANDING, IMPLYING SOME LOCALLY HEAVIER SNOWFALL RATES. BAND ITSELF
MOVING SOUTH AT A PRETTY GOOD CLIP AND IT CONTINUES TO LOOK LIKE A
MINOR SNOW PRODUCER, CERTAINLY LESS THAN ONE INCH AT THIS POINT.
THIS SNOW WILL CONTINUE TO WORK QUICKLY SOUTH THIS MORNING AS UPPER
LOW OVER NORTHERN INDIANA GETS INTO WEST VIRGINIA BY LATE MORNING.
THE SNOW PROBABLY WONT BE INTO THE DETROIT/ANN ARBOR METRO AREAS
UNTIL AFTER SUNRISE AND COULD TAKE A GOOD PART OF THE MORNING TO GET
IT THROUGH THE ENTIRE CWA.

FROM THAT POINT, LOW LEVELS PROGGED TO DRY MARKEDLY FROM NORTH TO
SOUTH THROUGH THE REMAINDER OF THE AFTERNOON, ALTHOUGH DIURNAL SC
WILL MOST CERTAINLY DEVELOP WHERE SKIES CAN CLEAR. PROBABLY WILL BE
SOME SCT AFTERNOON SNOW SHOWERS ONCE AGAIN AS WELL, WHICH WILL
DISSIPATE AT SUNSET. THE UNSEASONABLY COLD AIR IN PLACE WILL FEEL
EVEN COLDER AS SURFACE WINDS WILL GET UP INTO THE 15 TO 25 RANGE AS
SURFACE GRADIENT TIGHTENS BEHIND PRESSURE TROF LATER THIS MORNING.
THE GRADIENT REMAINS TIGHT ENOUGH OVERNIGHT TO KEEP WINDS UP AND
THIS WILL PREVENT TEMPS FROM CRATERING, DESPITE SIGNIFICANT LOSS OF
CLOUD COVER AFTER SUNSET. RECORD LOW AT KFNT OF 22 FOR WEDNESDAY
MORNING STILL DOABLE SHOULD WINDS DROP OFF MORE THAN EXPECTED.
PROBABLY SAFE TO SAY THAT KDTWS RECORD LOW OF 8 WILL STAND FOR
ANOTHER YEAR. LATEST GLRETA RUN SUGGESTS BULK OF LAKE EFFECT SNOWS
WILL BE OFFSHORE THE THUMB TONIGHT AS MEAN LOW LEVEL NORTHERLY FLOW
MAINTAINS A SLIGHT WEST COMPONENT. WEDNESDAY LOOKS DRY, ALTHOUGH
DIURNAL CU WILL LIKELY REMAIN A PROBLEM WITH RELATIVELY COLD 850MB
AIR STILL IN PLACE, HIGH SUN ANGLE AND WEAKLY CYCLONIC LOW LEVEL
FLOW. THEN THE WARMUP BEGINS AS AVN CONTINUES TO SHOW STRONG PLAINS
CYCLOGENESIS WHICH WILL FORCE LOW LEVEL WARM AIR ADVECTION TO ENSUE.
AVN TAKES SURFACE LOW INTO CENTRAL WI BY SATURDAY MORNING WHICH
SHOULD ALLOW TEMPS TO CLIMB QUICKLY BACK INTO AT LEAST THE 60S AND
PERHAPS HIGHER, DEPENDING ON AMOUNT OF CLOUDS/PRECIP.

.DTX...GALE WARNING THIS MORNING LAKE HURON.

JW