000
FXUS63 KDTX 201116
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
616 AM EST THU NOV 20 2008
.AVIATION...
CEILINGS WILL ALTERNATE BETWEEN MVFR AND VFR AS SCATTERED LIGHT SNOW
SHOWERS AND FLURRIES FALL ACROSS THE TAF SITES TODAY AS A WEAK TROF
MOVES THROUGH THE AREA. THE HEAVIEST SNOW WILL FALL EAST OF THE TAF
SITES WITH LAKE EFFECT SNOW...SO MVFR CONDITIONS ARE THE WORST THAT
ARE EXPECTED ACROSS THE TAF SITES. WIDESPREAD VFR CONDITIONS ARE
EXPECTED TO RETURN TO THE TAF SITES TONIGHT AS SKIES CLEAR OUT SOME
WITH DRIER AIR WORKING ITS WAY INTO THE REGION. WINDS WILL AGAIN
GUST TO 25 KNOTS TODAY...THEN SUBSIDE TO 20 KNOTS OR LESS TONIGHT.
&&
.PREV DISCUSSION...ISSUED 408 AM EST THU NOV 20 2008
SHORT TERM...TODAY
COLD NORTHWEST FLOW WILL PERSIST ACROSS THE AREA TODAY AS A WEAK
TROF MOVES THROUGH THE CWA. MOISTURE IS FAIRLY LIMITED AS TAMDAR
SOUNDINGS AT DTW SHOW MOISTURE ONLY TO 750 MB. BUFKIT SOUNDINGS DO
NOT SHOW MUCH OF AN INCREASE IN THE DEPTH OF THE AVAILABLE MOISTURE
THROUGHOUT THE DAY...HOWEVER THE EASTERN THUMB WILL PICK UP SOME
MOISTURE FROM LAKE HURON WITH A NORTH NORTHWESTERLY FLOW AS DELTA T
VALUES CLIMB INTO THE UPPER TEENS. SINCE THE TRAJECTORY OFF THE LAKE
IS NOT IDEAL FOR MORE THAN 1 TO 3 INCHES OF LAKE EFFECT SNOW DURING
THE DAY TODAY...WILL NOT ISSUE ANY HEADLINES FOR THE EASTERN THUMB
AT THIS TIME. WILL LOWER POPS FURTHER INLAND 5 TO 10 PERCENT TODAY
WITH THE LOWER MOISTURE CONTENT AWAY FROM LAKE HURON.
WINDS WILL AGAIN GUST INTO THE 20 TO 25 MPH RANGE TODAY AS MIXING
TAPS INTO THE HIGHER WINDS JUST ABOVE THE SURFACE. CLOUDY CONDITIONS
WILL CONTINUE...AS HIGH TEMPERATURES REMAIN IN THE 30S WITH THE LACK
OF SUNSHINE AND CONTINUED COLD NORTHWEST FLOW.
LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
COOL BUT PRIMARILY DRY WEATHER WILL CONTINUE THROUGH THE END OF THE
WEEK AS ANOTHER UPPER LEVEL WAVE OVER NORTHERN MANITOBA BRINGS A
REINFORCING SHOT OF COLD AIR TO THE REGION. RAOB DATA FROM CHURCHILL
MANITOBA DEPICTS TEMPERATURES OF -40C AT 500MB AND -20C AT 850MB.
THE GREAT LAKES WILL HELP TO MODERATE THIS ARCTIC AIRMASS AS IT
MOVES INTO THE REGION WHICH WAS ABLE TO LIMIT HIGHS NORTH OF LAKE
SUPERIOR TO THE LOW 20S ON WEDNESDAY. TEMPERATURES ON FRIDAY ARE
EXPECTED TO PEAK AROUND 30 DEGREES WITH A FEW BREAKS IN THE CLOUD
COVER. LOWS WILL BE QUITE COLD ON FRIDAY NIGHT WITH SKIES
SCATTERING OUT AND HIGH PRESSURE BUILDING OVERHEAD. TEMPERATURES
WILL FALL SOLIDLY INTO THE TEENS OUTSIDE OF THE DETROIT METRO AREA.
THE EXCEPTION TO THE DRY WEATHER WILL BE ALONG THE LAKE HURON
SHORELINE WHERE LAKE EFFECT SNOW SHOWERS MAY BRUSH THE EXTREME
EASTERN PORTIONS OF HURON...SANILAC AND ST CLAIR COUNTIES OVERNIGHT.
THE DOMINANT LAKE EFFECT BAND WILL LARGELY REMAIN OFFSHORE...AND
WILL SHIFT FURTHER OUT OVER THE LAKE AS HIGH PRESSURE BUILDS AND
SURROUNDING LAND AREAS COOL...STRENGTHENING THE THERMAL TROUGH OVER
THE LAKE.
A SHORTWAVE PASSES TO OUR SOUTH ON SATURDAY WITH LITTLE IMPACT ASIDE
FROM AN INCREASE IN MID LEVEL CLOUDS. OTHERWISE SOUTHERLY FLOW
INCREASES ON SUNDAY AHEAD OF THE NEXT LOW PRESSURE SYSTEM
APPROACHING FROM THE NORTHERN PLAINS. THE STRENGTHENING FLOW WILL
AIM TO BOOST TEMPERATURES TO NEAR 40 DEGREES...BRINGING OUR WARMEST
DAY IN NEARLY A WEEK. HAVE REMOVED CHANCES OF PRECIPITATION ACROSS
THE SOUTHERN HALF OF THE AREA AS THE SOUTHERLY FLOW ALSO PROVIDES AN
INFLUX OF DRY AIR FROM THE BROAD SURFACE HIGH TO OUR SOUTH. MOISTURE
APPROACHING WITH THIS SYSTEM WILL BE FOCUSED ALONG THE ELEVATED WARM
FRONT ACROSS CENTRAL AND NORTHERN LOWER MICHIGAN WHERE A CHANCE OF
LIGHT SNOW REMAINS. SCATTERED SNOW SHOWERS WILL RETURN ALONG THE
NEXT COLD FRONT LATE SUNDAY NIGHT AND CONTINUE UNDER THE COLD AIR
ADVECTION REGIME INTO THE EARLY PART OF NEXT WEEK.
MARINE...
LOW PRESSURE WILL TRACK SOUTHEAST INTO THE EASTERN GREAT LAKES
TODAY. STRONG NORTHWEST WINDS WILL CONTINUE BEHIND THE LOW TODAY.
STRONG LOW LEVEL COLD ADVECTION WILL ALSO ALLOW FOR UNSTABLE
CONDITIONS...WITH HIGH WAVES AND LAKE EFFECT SNOW SQUALLS INTO
FRIDAY. SURFACE HIGH PRESSURE SLOWLY BUILDING INTO THE CENTRAL GREAT
LAKES LATE FRIDAY AND SATURDAY WILL ALLOW FOR THE WINDS AND WAVES TO
SUBSIDE AND BRING AN END TO THE SNOW SHOWERS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL 7 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
HURON...UNTIL 10 AM SATURDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...UNTIL 4 AM SATURDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...UNTIL 7 AM FRIDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...UNTIL 7 AM FRIDAY.
&&
$$
AVIATION.....KURIMSKI
SHORT TERM...KURIMSKI
LONG TERM....KEC
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
