Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 260527
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1227 AM EST MON JAN 26 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 244 PM EST SUN JAN 25 2015

THE UPPER GREAT LAKES IS BETWEEN CLIPPER SYSTEMS THIS
AFTERNOON...WITH THE FIRST ONE MOVING INTO THE OHIO RIVER VALLEY AT
THIS TIME...WITH THE SECOND ONE ROUNDING THE UPPER RIDGE OVER THE
WESTERN CONUS. BETWEEN THESE TWO CLIPPERS...AN AREA OF HIGH PRESSURE
IS LOCATED OVER NORTHERN ONTARIO AND IS STRETCHING A RIDGE OVER THE
UPPER GREAT LAKES REGION. THIS RIDGE HAS LED TO WEAKENING WINDS OVER
THE CWA THROUGH THE DAY TODAY AND WHEN COMBINED WITH THE LOWERING
SUBSIDENCE INVERSION (SEEN ON KMQT VAD)...HAS DIMINISHED THE LAKE
EFFECT SNOW SHOWERS OVER THE AREA FROM THIS MORNING. BUT THERE ARE
STILL SNOW SHOWERS OVER THE NORTH CENTRAL AND KEWEENAW. THESE SNOW
SHOWERS WILL CONTINUE TO SLOWLY DIMINISH THROUGH THE EVENING AND
THEN WHAT IS LEFT OVER WILL SHIFT NORTH OVER LAKE SUPERIOR AS THE
SOUTHERLY WINDS DEVELOP AHEAD OF THE NEXT CLIPPER SYSTEM.

THAT NEXT CLIPPER SYSTEM (CURRENTLY MOVING THROUGH NORTHERN
SASKATCHEWAN) WILL DROP SOUTHEAST AND THROUGH THE AREA LATE TONIGHT
AND MONDAY. THERE ARE TWO EMBEDDED WAVES OF ENERGY ASSOCIATED WITH
THIS CLIPPER SYSTEM THAT WILL AFFECT THE AREA. THE FIRST WAVE WILL
MOVE INTO THE MINNESOTA ARROWHEAD SHORTLY AFTER 06Z TONIGHT AND THEN
QUICKLY DIVE SOUTHEAST ACROSS WESTERN LAKE SUPERIOR AND NORTHWEST
WISCONSIN BY 12Z MONDAY. THE SECOND WAVE WILL TRACK A TOUCH FARTHER
TO THE NORTHEAST AND WILL BE ASSOCIATED WITH THE WEAKENING SURFACE
LOW MOVING ACROSS WESTERN LAKE SUPERIOR MONDAY AFTERNOON. THERE HAS
DEFINITELY BEEN A SOUTHWEST TREND IN THE TRACK OF THESE WAVES OVER
THE LAST 24HRS...SO HAVE CONTINUED THAT TREND WITH THIS FORECAST.
WITH THE TRACK OF THE TWO WAVES...WILL SHOW INCREASING POPS OVER THE
WEST-SOUTHWEST HALF OF THE CWA OVERNIGHT TONIGHT (HIGHEST NEAR
IRONWOOD). BASED OFF THE TRACK OF THE SHORTWAVE AND BEST 850-500MB
WARM AIR ADVECTION AND Q-VECTOR CONVERGENCE...THINK THE BEST
PRECIPITATION WILL BE SOUTHWEST OF THE CWA BUT STILL SHOULD SEE 1-2
INCHES OF SNOW OVER THE WESTERN THIRD OF UPPER MICHIGAN THROUGH
MONDAY MORNING. THEN AS THE SECOND WAVE MOVES THROUGH LATE MONDAY
MORNING THROUGH EARLY EVENING...SHOULD SEE A MORE BROAD/LIGHT SNOW
SPREADING SOUTHEAST OVER THE MUCH OF THE REST OF THE CWA. ONCE
AGAIN...SNOWFALL AMOUNTS SHOULD BE LIGHT WITH THIS SECOND WAVE AND
GENERALLY UNDER AN INCH.

THERE IS ONE OTHER ITEM OF CONCERN WITH THIS CLIPPER SYSTEM...LAKE
EFFECT/ENHANCED SNOW OFF LAKE MICHIGAN. AS THE SOUTH-SOUTHEAST FLOW
DEVELOPS OVER THE LAKE LATE TONIGHT AND MONDAY MORNING...875MB TEMPS
ARE STILL HOVERING AROUND -12 TO -13C AND PROVIDING DECENT DELTA-T
VALUES OVER THE LAKE. MODELS ARE INDICATING THERE BEING ENOUGH DRY
AIR AND SUBSIDENCE IN PLACE MONDAY MORNING TO LIMIT SNOW
DEVELOPMENT...BUT AS THE DEEPER MOISTURE ARRIVES IN THE AFTERNOON
WITH THE SECOND WAVE SHOULD SEE THE SNOW DEVELOP. THERE IS A LITTLE
BIT OF A CONCERN IN THE SHEAR IN THE CLOUD LAYER (SOUTHEAST WINDS AT
THE SURFACE...SOUTH MID CLOUD...AND SOUTHWEST AT THE TOP OF THE
CLOUD)...WHICH COULD HELP LIMIT THE INTENSITY OF THE SNOW. BASED OFF
THE CONSISTENCY IN THE HIGHER RESOLUTION MODELS...DID TREND THE POPS
UP TO LIKELY-DEFINITE VALUES OVER DELTA/SCHOOLCRAFT COUNTIES (AND
EVEN WESTERN ALGER) TO HIGHLIGHT THAT LAKE EFFECT SNOW POTENTIAL.
CURRENTLY HAVE AMOUNTS IN THE 1-2 INCH RANGE...BUT THERE COULD BE A
NARROW BAND OF HIGHER AMOUNTS DEPENDING ON THE EXACT LOCATION OF
WHERE THINGS SETUP.

CLEARING INITIALLY OVER PARTS OF THE AREA WILL LEAD TO A QUICK FALL
IN TEMPS THIS EVENING BEFORE SOUTHERLY FLOW AND HIGH CLOUDS
DEVELOP/MOVE OVER THE AREA OVERNIGHT. WITH DEWPOINTS IN THE MID-
LOWER SINGLE DIGITS ABOVE ZERO IN AREAS THAT CLEARED...HAVE USED
THAT AS A STARTING POINT AND WENT WITH LOWS AROUND 4-7 DEGREES BELOW
THAT. IT SHOULD BE SHORT LIVED LOWS...AS TEMPERATURES SLOWLY RISE
FROM WEST TO EAST AS THE CLOUDS INCREASE. HIGHS ON MONDAY SHOULD BE
AROUND OR SLIGHTLY ABOVE NORMAL (20S).

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 1039 PM EST SUN JAN 25 2015

ORIGINALLY SHOULD HAVE BEEN ISSUED AROUND 4 PM SUNDAY...WITH NO
UPDATES SINCE THEN...

NAM SHOWS A DEEP 500 MB TROUGH OVER THE EASTERN U.S. WITH A STRONG
RIDGE OVER THE ROCKIES 00Z TUE. THIS RIDGE WEAKENS AS IT MOVES INTO
THE PLAINS ON TUE. NAM...GFS AND ECMWF SHOW 850-500 MB Q-VECTOR
CONVERGENCE MOVING INTO UPPER MICHIGAN ON WED.

WILL CONTINUE WITH CHANCE POPS FOR MON NIGHT AS A WEAK SYSTEM MOVES
THROUGH. THE MOISTURE FROM THIS SYSTEM DEPARTS ON TUE AND SHOULD BE
DRY FOR TUE NIGHT. ON WED...POPS WILL SLOWLY MOVE SOUTH ACROSS THE
CWA WITH CHANCE POPS ACROSS THE NORTHERN CWA BY LATE WED AFTERNOON.
DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST OVERALL.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE UPPER
GREAT LAKES 12Z THU WITH AN ALBERTA CLIPPER SYSTEM TO THE SOUTH OF
THE AREA. THIS CLIPPER WILL BRING IN SOME COLDER AIR ON FRI WITH
MORE UPPER TROUGHING FOR SAT WITH ANOTHER CLIPPER MOVING THROUGH THE
AREA. THIS CLIPPER HELPS TO CARVE OUT A BROAD AND DEEP 500 MB TROUGH
OVER THE EASTERN U.S. ON SUN. TEMPERATURES WILL FALL AND STAY BELOW
NORMAL FOR THIS FORECAST PERIOD. HAVE CHANCE POPS FOR WED NIGHT WITH
PASSAGE OF AN ALBERTA CLIPPER.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1227 AM EST MON JAN 26 2015

A CLIPPER SYSTEM DROPPING SE THROUGH SRN MANITOBA WILL MOVE ACROSS
THE AREA OVERNIGHT INTO MONDAY. VFR CONDITIONS WILL GIVE WAY TO
GRADUALLY LOWERING CEILINGS AHEAD OF THE SYSTEM AND THEN SNOW MOVING
IN AT KIWD JUST AFT 12Z...AT KCMX LATE MON MORNING AND THEN AT KSAW
EARLY MON AFTERNOON. EXPECT IFR VSBYS TO AFFECT KIWD FROM MON MORNING
INTO EARLY AFTERNOON AND THEN IFR VBSYS WILL SPREAD INTO KCMX AND
KSAW LATE MON AFTERNOON INTO MON EVENING AS MOISTURE DEEPENS OVER THE
NW AND NCNTRL PORTION OF THE U.P. SOME IMPROVEMENT IN VSBY IS
EXPECTED AT KIWD LATE MONDAY AS BEST MOISTURE DEPARTS AND SNOW TAPERS
OFF.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 244 PM EST SUN JAN 25 2015

A HIGH PRESSURE RIDGE MOVING ACROSS LAKE SUPERIOR WILL CONTINUE TO
WEAKEN WINDS THROUGH THE EVENING HOURS...BEFORE INCREASING OUT OF
THE SOUTH THROUGH THE REST OF THE NIGHT AHEAD OF A CLIPPER SYSTEM.
THIS CLIPPER SYSTEM WILL MOVE SOUTHEAST THROUGH NORTHWEST WISCONSIN
WHILE WEAKENING. THE SOUTHERLY FLOW AHEAD OF THE CLIPPER WILL LEAD
TO WINDS OF 20-30KTS LATE TONIGHT INTO MONDAY. A HIGH PRESSURE
RIDGE BUILDING INTO THE UPPER GREAT LAKES REGION ON MONDAY NIGHT
WILL DIMINISH WINDS BELOW 15KTS BY LATE MONDAY NIGHT AND WILL
REMAIN THROUGH TUESDAY. A LOW PRESSURE SYSTEM DEVELOPING IN THE
NORTHERN/CENTRAL PLAINS ON TUESDAY NIGHT WILL SHIFT EAST INTO THE
MID MISSISSIPPI VALLEY BY WEDNESDAY NIGHT...SHIFTING A TROUGH EAST
ACROSS THE UPPER GREAT LAKES REGION. WINDS ASSOCIATED WITH THIS
TROUGH WILL LIKELY STAY BELOW 25KTS.
&&

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

$$

SHORT TERM...SRF
LONG TERM...07
AVIATION...VOSS
MARINE...SRF


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