Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 201958
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
358 PM EDT SUN APR 20 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 357 PM EDT SUN APR 20 2014

QUITE THE DIFFERENCE IN CONDITIONS FROM THE LAKE MICHIGAN SHORELINE
TO THE WESTERN HALF OF UPPER MICHIGAN. THE AREA OF SHOWERS THAT
MOVED THROUGH UPPER MICHIGAN LAST NIGHT AND INTO THE EARLY MORNING
HOURS SLOWLY SLID SOUTHEAST THIS AFTERNOON AND IS NOW MAINLY
LOCATED IN NORTHERN LAKE MICHIGAN. THE CLOUDS AND RAIN (SOME
LOCATIONS ALONG THE SHORELINE SEEING 0.5-0.6IN OF ACCUMULATION) HAS
HELD TEMPS DOWN AND MAINLY IN THE UPPER 30S AND LOWER 40S (AIDED BY
SOUTHERLY WINDS OFF THE LAKE). MEANWHILE...JUST A SHORT DISTANCE TO
THE WEST AND THE SUNSHINE HAS HELPED TEMPERATURES RISE INTO THE
UPPER 50S AND LOWER 60S OVER CENTRAL UPPER MICHIGAN AND THE UPPER
60S TO A FEW 70S AT THE RAWS SITES IN THE WESTERN U.P. THIS
SUNSHINE AND DEEPER MIXING INTO THE DRIER AIR ALOFT INDICATED ON
THE 12Z KINL RAOB HAS ALLOWED DEWPOINTS TO FALL INTO THE LOWER 30S
OVER THE WESTERN U.P.

OVERALL...THERE WILL BE TWO FEATURES THAT WILL BE INFLUENCING THE
PRECIPITATION CHANCES FOR UPPER MICHIGAN TONIGHT AND MONDAY.
FIRST...THE THE PERSISTENT MID LEVEL MOISTURE PLUME THAT IS
CURRENTLY STRETCHING FROM NORTHERN IOWA THROUGH NORTHERN LAKE
MICHIGAN AND INTO ONTARIO. MODELS HAVE BEEN STRUGGLING WITH HOW FAR
NORTH THIS FEATURE TRACKS TONIGHT INTO MONDAY...IN ADDITION TO ITS
INTERACTION WITH THE NEXT WAVE MOVING THROUGH ON MONDAY. THIS
MORNING THERE WAS MORE OF A SOUTHWESTERLY COMPONENT TO THE
FLOW...AS THE UPPER LOW WAS LOCATED IN FAR NORTHERN ONTARIO. BUT
WITH THE EXPECTED TRACK TO THE EAST OF THIS UPPER LOW AND A WEAK
UPPER RIDGE OVER LAKE WINNIPEG EXPECTED TO SHIFT EAST INTO NORTHERN
ONTARIO TONIGHT...WOULD EXPECT THE 700-500MB FLOW TO BECOME A
LITTLE MORE WESTERLY. THIS WESTERLY FLOW SHOULD ALLOW THE DRIER AIR
SEEN ON THE 12Z KABR/KBIS/KINL SOUNDINGS TO CONTINUE TO SHIFT OVER
MUCH OF THE AREA AND HELP KEEP THE SHOWERS AT BAY. STILL THINK THE
SOUTH CENTRAL CWA COULD SEE A FEW SHOWERS TONIGHT AND SOME MID CLOUD
COVER AS THE 850MB FLOW TAKES A LITTLE LONGER TO VEER TO THE WEST.
WILL KEEP RAINFALL AMOUNTS ON THE LIGHT SIDE SINCE THE BETTER
MOISTURE AND PRECIPITATION SHOULD STAY TO THE SOUTH OF THE CWA. FOR
THE REST OF THE CWA...THE CLEARING SEEN THIS MORNING AND CONTINUING
THROUGH THE AFTERNOON SHOULD REMAIN IN PLACE DUE TO THE DRY AIR
MENTIONED PREVIOUSLY AND A WEAK HIGH PRESSURE RIDGE MOVING IN. THESE
CLEAR SKIES AND LIGHT WINDS WILL ALLOW FOR RADIATIONAL COOLING AND
ALLOW TEMPERATURES TO FALL INTO THE LOWER 30S OVER THE NORTHERN HALF
OF THE CWA. THERE IS THE POTENTIAL SOME LOCATIONS COULD EVEN FALL
INTO THE UPPER 20S...WHICH WOULD BE A TOUCH BELOW NORMAL. WITH THESE
FALLING TEMPS AND LIGHT WINDS...IT LEADS TO THE POTENTIAL FOR SOME
FOG DEVELOPMENT. THE DEEPER MIXING HAS ALLOWED AFTERNOON DEWPOINTS
OVER THE WEST TO FALL INTO THE LOWER 30S...WHILE THE CENTRAL CWA IS
STILL IN THE LOW-MID 40S WITH THE CLOSER PROXIMITY TO THE DEPARTING
CLOUDS. USING THOSE VALUES AS THE CROSSOVER TEMP TO GET A ROUGH
IDEA...WOULD EXPECT GROUND FOG TO OCCUR OVER MUCH OF THE
NORTH-NORTHWESTERN 2/3RDS OF THE U.P. THEREFORE...WILL CONTINUE TO
MENTION PATCHY FOG AWAY FROM THE MORE CLOUDY SOUTH CENTRAL AND DID
TREND UP TOWARDS AREAS OF FOG OVER THE CENTRAL U.P. WHERE THE
CROSSOVER TEMPERATURE VALUES ARE MORE SUPPORTIVE.

FOR MONDAY...THE LOCATION OF THE PRECIPITATION IN THE MORE WESTERLY
FLOW BRUSHING THE AREA WILL REMAIN A CONCERN...ALONG WITH A
SHORTWAVE MOVING THROUGH THE AREA. THIS SHORTWAVE IS CURRENTLY
DEPARTING THE ROCKIES ALONG THE US/CANADIAN BORDER AND IS EXPECTED
TO CONTINUE THAT TRACK ALONG THE BORDER TONIGHT AND
MONDAY...REACHING NORTHERN LAKE SUPERIOR BETWEEN 18Z-00Z. AN
ASSOCIATED BROAD SURFACE LOW STRETCHING FROM SOUTHERN CANADA AND
INTO THE NORTHERN CONUS WILL SHIFT EAST THROUGH THE WESTERN GREAT
LAKES REGION ON MONDAY. AS HAS BEEN THE CASE OVER THE LAST SEVERAL
DAYS...MODELS CONTINUE TO STRUGGLE WITH THE SOUTHWARD EXTENT OF THIS
WAVE AND POTENTIAL MERGING WITH THE EXISTING MID LEVEL MOISTURE
STREAM ALONG AND SOUTH OF THE SOUTHERN EDGE OF THE CWA. WITH THE
BULK OF THE FORCING FROM THE SHORTWAVE STAYING NORTH OF THE AREA
(ALTHOUGH THE SOUTHWEST EDGE DOES SWEEP OVER THE WESTERN CWA LATE
IN THE AFTERNOON) AND LIMITED MOISTURE SEEN ON THE SOUTHERN SIDE OF
THE SHORTWAVE...HAVE TO THINK THE NORTHWARD EXTENT OF THE SOUTHERN
FEATURE WILL DETERMINE PRECIPITATION CHANCES. WITH THE MORE
WESTERLY FLOW EXPECTED TONIGHT...FEEL THAT THE SOUTHERN STREAM
MOISTURE WILL BE FAIRLY SUPPRESSED TO THE SOUTH. THUS...LIKE THE
GENERALLY DRY IDEA SHOWN BY THE 12Z NAM/GFS/ECMWF FOR TOMORROW. THE
GEM-REGIONAL SHOVE HIGHER DEWPOINTS INTO THE AREA (LOWER 50S
OVER THE SOUTH HALF) DURING THE DAY TOMORROW AND IF THE BOUNDARY
SHIFTS FARTHER TO THE NORTH THAT MAY BE REASONABLE. BUT WITH THE
DRY AIR IN PLACE AND SOME FILTERED SUNSHINE WITH THE INCREASING
10-15KFT CLOUDS AHEAD OF THE SHORTWAVE...DON/T THINK DEWPOINTS WILL
GET THAT HIGH (ML DEWPOINTS WITH MOST MODELS IN THE LOWER 40S EAST
AND UPPER 30S WEST IN THE AFTERNOON DEPENDING ON WHEN THE LOW
MOVES THROUGH). THUS...WOULD EXPECT THE INSTABILITY SHOWN ON
THE GEM-REGIONAL (MLCAPES OF 300-700J/KG) TO BE OVERDONE AND LARGELY
DRIVING THE PRECIPITATION IT DEVELOPS. DUE TO THOSE
EXPECTATIONS...HAVE TRENDED POPS DOWN FOR THE MORNING HOURS AND
CONFINED TO THE SOUTH CENTRAL. DID LEAVE SOME ISOLATED POPS IN FOR
THE AFTERNOON HOURS DUE TO THE STRENGTH OF THE SHORTWAVE AND
COLD AIR DROPPING INTO THE CWA FROM THE NORTHWEST. IF THE SOUNDINGS
END UP AS DRY AS SHOWN ON THE 12Z NAM/GFS...DON/T EVEN THINK THE
STRENGTH OF THE SHORTWAVE WILL LEAD TO ANY PRECIPITATION. AS FOR
TEMPS...SHOULD SEE ANOTHER NORMAL TO ABOVE NORMAL TEMPERATURE DAY
FOR THE INTERIOR LOCATIONS AND NORMAL NEAR THE LAKE SHORES. MIXING
TO 900-850MB TEMPS SHOWN ON THE NAM WOULD YIELD HIGHS IN THE 60S FOR
INTERIOR LOCATIONS. LIGHT WINDS AND WARMING TEMPS SHOULD PRODUCE
LAKE BREEZES OFF LAKE MICHIGAN/SUPERIOR AND KEEP VALUES A LITTLE
COOLER. THEN AS WINDS TURN WESTERLY FROM WEST TO EAST IN THE
AFTERNOON BEHIND THE BROAD LOW PRESSURE AREA...WOULD EXPECT COOLING
OVER THE WEST WITH WINDS OFF THE ICE.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EDT SUN APR 20 2014

LINGERING FOG SHOULD QUICKLY DISSIPATE MONDAY MORNING AS BETTER
MIXING RETURNS AND TEMPERATURES QUICKLY SHOOT UP INTO THE 50S. THE
INITIAL LOW STRETCHING FROM JUST N OF THE MN BORDER THROUGH NE IA AT
12Z WILL SHIFT OVER THE UPPER GREAT LAKES THROUGH THE DAY...BEFORE
EXITING ACROSS THE LOWER GREAT LAKES OVERNIGHT. WILL KEEP THE
MENTION OF TS OUT OF THE FCST FOR MONDAY...AS THE BEST CHANCE
REMAINS S OF THE WI BORDER. EXPECT A QUICK TENTH OF AN INCH OR LESS
OF RAIN ACROSS MUCH OF THE CWA DURING THE DAY MONDAY.

HIGH PRESSURE WILL THEN BE THE RULE TUESDAY AND WEDNESDAY...AHEAD OF
THE MAIN EVENT LATER THIS WEEK...WITH MAINLY DRY WEATHER FIGURED.
THERE MAY BE A FEW LINGERING RAIN/SNOW SHOWERS TUESDAY MORNING OVER
THE E. THE SFC HIGH SHOULD BE NEARLY OVERHEAD AT 06Z WEDNESDAY.
DECREASED WINDS AND LOWERED MORNING TEMPS SLIGHTLY TUESDAY
NIGHT/WEDNESDAY MORNING.

ALTHOUGH TIMING AND LOCATION OF THE LOW PRESSURE SYSTEM FOR THE END
OF THE WEEK IS STILL A BIT UP IN THE AIR...THE MODELS DO AGREE UPON
STRONG 850-925MB WINDS STILL 35-50KTS THURSDAY AFTERNOON AND
EVENING. WILL NOT GET INTO TOO MANY OF THE SPECIFICS OTHER THAN TO
NOTE THAT TEMPS SHOULD COOL ENOUGH TO RESULT IN A MIX OF RAIN/SNOW
FRIDAY EVENING...IF NOT ALL SNOW BEFORE ENDING.

LARGE 1036MB INCH HIGH PRESSURE RESIDING ACROSS MUCH OF CENTRAL
CANADA DURING THE END OF THE WORK WEEK WILL BUILD TO NEAR 1044MB
OVER HUDSON BAY OVER THE WEEKEND. THE RESULT WILL BE A SIGNIFICANT
RIDGE EXTENDING ACROSS LAKE SUPERIOR/UPPER MI WHENEVER THE SFC LOW
SHIFTS E ON SATURDAY.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 104 PM EDT SUN APR 20 2014

VFR CONDITIONS WILL PREVAIL THROUGH THE FIRST HALF OF THE TAF
FORECAST PERIOD...AS DRY AIR HAS SURGED OVER THE THREE TAF SITES.
THIS WILL CONTINUE INTO THE EVENING HOURS WITH WINDS COMING OFF
LAKE SUPERIOR. HEADING INTO TONIGHT...THE MAIN QUESTION MARK IS
IF/WHEN RADIATIONAL FOG DEVELOPS. HAVE FOLLOWED MOS GUIDANCE FOR
MUCH OF THE TIMING ON THE FOG AND INTENSITY. KIWD MAY END UP BEING
THE HIGHEST WITH VERY LIGHT AND UNFAVORABLE SOUTHEAST FLOW
DEVELOPING LATER TONIGHT AND LIKELY LIMITING VISIBILITY
RESTRICTIONS. A LITTLE CONCERNED WITH DRIER AIR OVER LAKE SUPERIOR
INFLUENCING KCMX AND HAVE NOT WENT AS LOW AS INDICATED BY SOME OF
THE MOS. AS FOR KSAW...THINK THEY HAVE THE BEST OPPORTUNITY TO FALL
TO LIFR BASED OFF THE HIGHER DEWPOINTS THIS AFTERNOON...THE CLOSER
PROXIMITY TO THE MOISTURE TO THE SOUTHEAST...AND LIGHT
SOUTH-SOUTHEAST UPSLOPE FLOW DEVELOPOING OVERNIGHT. EXPECT THE FOG
TO BURN OFF DURING THE MORNING AS MIXING INCREASE AND SOME MID
CLOUDS TO APPROACH TOWARDS AFTERNOON.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 PM EDT SUN APR 20 2014

GENERALLY LIGHT WINDS (LESS THAN 20KTS) ARE EXPECTED OVER THE NEXT
24 HOURS AS A WEAK HIGH PRESSURE RIDGE MOVES IN THIS EVENING. A
BROAD AREA OF LOW PRESSURE WILL MOVE ACROSS LAKE SUPERIOR MONDAY
AFTERNOON AND LEAD TO INCREASING NORTHWESTERLY WINDS MONDAY NIGHT
AND CONTINUING INTO TUESDAY. THE STRONGEST WINDS WILL BE OVER
EASTERN LAKE SUPERIOR WITH GUSTS UP TO 25KTS. ANOTHER AREA OF HIGH
PRESSURE WILL MOVE OVER THE AREA ON TUESDAY NIGHT AND REMAIN INTO
WEDNESDAY EVENING...PRODUCING ANOTHER PERIOD OF LIGHT WINDS. A LOW
PRESSURE SYSTEM MOVING OUT OF THE NORTHERN PLAINS ON WEDNESDAY
NIGHT WILL BRING INCREASING SOUTHEASTERLY FLOW ON THURSDAY. AT THIS
TIME...WINDS APPEAR TO STAY BELOW 25KTS FOR THURSDAY AND
FRIDAY...AS THE LOW MOVES THROUGH THE GREAT LAKES REGION.
&&

.HYDROLOGY...
ISSUED AT 434 AM EDT SUN APR 20 2014

AS NOTED IN THE PREVIOUS HYDROLOGY DISCUSSION...
WARMER TEMPERATURES WILL RESULT STEADY MELTING...SLOWED DOWN
SLIGHTLY EACH EVENING/OVERNIGHT AS DAILY MINIMUM TEMPERATURES RETURN
INTO THE LOW TO MID 30S OR COOLER THROUGH THE WORK WEEK. HIGHS TODAY
WILL AVERAGE 5-15 DEGREES ABOVE NORMAL TODAY AND MONDAY...BEFORE
RETURNING CLOSER TO NORMAL THROUGH THE REST OF THE WEEK.

THE HEAVY SNOWFALL THIS PAST THURSDAY ACROSS W UPPER MI HAS
REPLENISHED SOME OF THE WATER CONTENT THAT WAS LOST DURING THE WARMER
CONDITIONS OVER THE PAST COUPLE OF DAYS. THE W HIGH TERRAIN /AS OF
FRIDAY MORNING/ HAD 6 TO 8 INCHES OF WATER EQUIVALENT...WITH
LOCALIZED 10 INCH AMOUNTS.

ALTHOUGH WIDESPREAD FLOODING IS NOT A CONCERN AT THIS TIME...ANY
RIVER THAT HAS ICE REMAINING ON IT...ESPECIALLY THE ESCANABA RIVER IN
DELTA COUNTY...COULD EXPERIENCE AN ICE JAM WITH THE RISING RIVER
LEVELS THIS WEEK. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS
SHOULD MONITOR BOTH RIVER LEVELS AND ICE CONDITIONS. ICE JAMS CAN
FORM AND BREAK QUICKLY...RESULTING IN RAPIDLY FLUCTUATING RIVER
LEVELS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...SRF
LONG TERM...KF
AVIATION...SRF
MARINE...SRF
HYDROLOGY...KF






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