AREA FORECAST DISCUSSION
NWS GAYLORD MI
AFDAPN 420 AM EST TUE JAN 16 2001
UPPER LEVEL JET/TROUGH DROPPING INTO CENTRAL CANADA IS FINALLY
PUSHING UPPER LOW OVER GREAT LAKES TO THE EAST. TROUGH WILL CROSS
FORECAST AREA TONIGHT WITH WEAK RIDGING OVER REGION WEDNESDAY.
ANOTHER NORTHERN STREAM TROUGH APPROACHES REGION THURSDAY. AT THE
SURFACE LOW MOVES AWAY TODAY WITH YET ANOTHER CLIPPER TYPE LOW
MOVING THROUGH ONTARIO WEDNESDAY NIGHT...DRAGGING A COLD FRONT
ACROSS THE REGION THURSDAY. PROBLEMS FOR THE FORECAST PERIOD BECOME
CLOUD COVER THROUGHOUT FORECAST...AND ANY PRECIPITATION TODAY.
ETA AND AVN VERY CLOSE EARLY ON IN FORECAST PERIOD...BUT DIVERGE A
LITTLE TOWARD THURSDAY. AVN SLOWER WITH SECOND CLIPPER AND AS USUAL
HAS QUITE A BIT MORE MOISTURE THAN ETA. WILL LEAN TOWARDS ETA
SOLUTION WHICH HAS BEEN SLIGHTLY MORE CONSISTANT AS PER HEMISPHERIC
MAP DISCUSSION FROM NCEP.
TODAY...LIGHT "NON-DESCRIPT" PRECIPITATION CONTINUING THIS
MORNING...BUT HAVE NOTICED A DIMINISHING TREND PAST FEW HOURS. LOOKS
LIKE PASSAGE OF ARCTIC FRONT IS HELPING TO DRY LOW LEVELS AND THUS
ENDING PRECIPITATION. FRONT SEEMS TO BE IN THE OSC-TVC AREA BY 18Z
THIS AFTERNOON BASED ON 06Z MESOETA/RUC. UPPER DIVERGENCE FORECAST
BY ETA OVER REGION TODAY WITH RIGHT ENTRANCE REGION OF 70KT 300MB
JETLET OVER ONTARIO. JET VERIFIED BY ACARS DATA AT 06Z. MID LEVEL
MOISTURE ALREADY PEELING OUT TO THE EAST TODAY...SO WITH WEAK LIFT
PROVIDED BY JET AND CLOUD TOP TEMPS ABOVE OR AROUND -10C COULD STILL
SEE PERIOD OF FLURRIES AND FREEZING DRIZZLE SOUTH OF FRONT WHERE LOW
LEVEL MOISTURE REMAINS.
COLDER AIR BEHIND FRONT /850MB TEMPS DROPPING TO AROUND
-15C OVER LAKE SUPERIOR AND -10C OVER LAKE MICHIGAN/ WILL LIKELY
GENERATE SOME CLOUDS AND MAYBE A FEW SNOW SHOWERS. HOWEVER...NORTH
TO NORTHEAST FLOW OVER EASTERN UPPER SHOULD KEEP SNOW SHOWERS TO THE
WEST. IN NORTHERN LOWER...NORTHWEST FLOW...DELTA T AROUND
15C...INVERSION HEIGHT AROUND 2KFT...ALL MEAN JUST SCATTERED SNOW
SHOWERS BEHIND ARCTIC FRONT.
TONIGHT...NORTHWEST 1000-850MB FLOW CONTINUES OVER NORTHERN
LOWER...NORTH OVER EASTERN UPPER. DELTA T/S INCREASE TO AROUND 17C
BUT INVERSION HEIGHTS CONTINUE TO FALL TO AROUND 1500FT. WILL KEEP
SOME CLOUDS IN NORTHWEST LOWER...BUT OTHER AREAS SHOULD BE ABLE TO
SEE SOME CLEARING WITH TROUGH MOVING AWAY LATE/RIDGING MOVING IN.
NORTHEAST SURFACE WINDS OVER SSM OVERNIGHT ALWAYS MEANS A BIG DROP
IN TEMPS.
WEDNESDAY...850MB THERMAL TROUGH MOVES AWAY EARLY WHICH SHOULD
HELP REGION SEE AT LEAST SOME SUNSHINE. COLDER WITH 850MB TEMPS
STARTING OUT AROUND -15C. 850MB TEMPS WARMING /DELTA T RISES TO
AROUND 10C/ AND RIDGING THROUGH 500MB SHOULD KEEP LAKE EFFECT FROM
DEVELOPING.
WEDNESDAY NIGHT...MOISTURE AHEAD OF 2ND CLIPPER MOVES INTO EASTERN
UPPER...PASSAGE OF COLD FRONT OVERNIGHT SHOULD PROVIDE ENOUGH
FORCING FOR LIGHT SNOW TO FALL. REST OF REGION PARTLY CLOUDY BEFORE
DEEPER MOISTURE ARRIVES THURSDAY. INCREASING SOUTHWEST FLOW
WEDNESDAY NIGHT SHOULD KEEP TEMPS FROM FALLING MUCH.
NO CHANGES NEEDED FOR THURSDAY BASED ON 00Z AVN.
NGM/AVN GUIDANCE TEMPS ARE CLOSE...WENT BELOW GUIDANCE TONIGHT WHERE
CLEARING OCCURS. OTHERWISE...FORECAST CLOSE TO GUIDANCE TEMPS.
.APX...NONE.
FARINA