Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 272013
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
313 PM EST TUE JAN 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM EST TUE JAN 27 2015

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALOFT OVER
THE GREAT LKS BTWN HI AMPLITUDE RDG OVER THE ROCKIES AND DEEP TROF
OVER THE E SUPPORTING INTENSE WINTER STORM THAT IS IMPACTING NEW
ENGLAND. SHRTWV DIGGING SEWD WITHIN THIS NW FLOW/DEEPER CLDS THAT
CAUSED PERIOD OF SN LAST EVNG ARE NOW SE OF THE AREA...SO LINGERING
LIGHT SN OVER THE CENTRAL CWA IS DIMINISHING WITH THE APRCH OF
SHRTWV RDG AXIS/DNVA/DEEP LYR QVECTOR CNVGC AND DRIER MID LVL AIR
SHOWN ON THE 00Z INL/YPL RAOBS. THESE RAOBS SHOW SOME LLVL MSTR BLO
INVRN...SO PLENTY OF LO CLDS LINGER UPSTREAM OVER NRN MN/NW ONTARIO.
HOWEVER...WITH 00Z H85 TEMP ONLY -5C AT INL...THE INCOMING AIRMASS
IS NOT SUFFICIENTLY COLD TO SUPPORT LES. COLDER AND DRIER LLVL AIR
IS STILL PRESENT TOWARD THE E AND ARCTIC HI PRES IN QUEBEC...WITH
MOCLR SKIES REPORTED EARLY THIS MRNG AT NEWBERRY AND THE SAULT.

MAIN FCST CONCERNS FOR TODAY/TNGT WL BE CLD TRENDS/IMPACT ON TEMPS.

TODAY...UPR MI WL BE DOMINATED BY DNVA/DEEP LYR QVECTOR DVGC
ASSOCIATED WITH APRCHG SHRTWV RDG. SO AFTER ANY LINGERING LIGHT SN
ENDS EARLY THIS MRNG...THE DAY SHOULD BE DRY AS SFC RDG AXIS
EXTENDING WSW FM THE HI CENTER IN QUEBEC SHIFTS OVER THE CWA.
DESPITE THE MID LVL DRYING...LINGERING LLVL MSTR TRAPPED BLO
LOWERING/STRENGTHENING SUBSIDENCE INVRN WL LIKELY MAINTAIN GENERALLY
MOCLDY SKIES...IN LINE WITH UPSTREAM OBS. ONE EXCEPTION SHOULD BE
THE ERN CWA...WHERE LIGHT E WIND WL MAINTAIN THE LLVL DRY AIR AND
ALLOW FOR MOSUNNY SKIES. ANOTHER AREA THAT MAY SEE SOME CLRG IS NEAR
LK SUP OVER THE NW CWA WHERE THE LLVL SW FLOW ON THE NRN FLANK OF
THE SFC RDG AXIS WL DOWNSLOPE AND RESULT IN LOWERING THE INVRN BASE
FURTHER. GOING FCST HI TEMPS MAINLY IN THE 20S...COLDEST OVER THE
E AND WARMEST OVER THE W...LOOK TO BE IN GOOD SHAPE.

TNGT...A SHRTWV IS FCST TO TRACK THRU FAR NRN ONTARIO. ALTHOUGH
LINGERING SHRTWV RDG AXIS WL FORCE THIS DISTURBANCE TO PASS TOO FAR
TO THE N TO BRING PCPN TO ALL BUT FAR NRN LK SUP LATE...AN INCRSG
LLVL ACYC SW FLOW BTWN THE SFC RDG AXIS SLIDING OVER LOWER MI AND
FALLING MSLP IN ONTARIO ASSOCIATED WITH THE PASSING SHRTWV WL ADVECT
SOME DRIER AIR INTO THE CWA. THIS DRYING PLUS MORE LLVL SUBSIDENCE
ASSOCIATED WITH THE STRENGTHENING ACYC FLOW WL LIKELY BREAK UP THE
LO CLDS OVER MUCH OF THE CWA...ESPECIALLY OVER NW NEAR LK SUP WHERE
SW WINDS DOWNSLOPE. OVER THE E...THE SW FLOW OFF LK MI MIGHT DRAW
MORE LO CLDS INTO THAT AREA. DESPITE ANY CLRG OF THE LOWER CLDS...
STRONGER WINDS AND INCRSG MID/HI CLDS ON THE SRN FLANK OF THE
DISTURBANCE PASSING TO THE N WL LIMIT THE DIURNAL TEMP FALL. EXPECT
THE LOWEST MIN TEMPS OVER THE E...WHERE TEMPS WL FALL OFF QUICKLY IN
THE EVNG BEFORE THE WINDS HAVE A CHC TO PICK UP A BIT OR ANY
CLDS ROLL IN LATER.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 313 PM EST TUE JAN 27 2015

AN UPPER RIDGE OVER THE WESTERN COAST OF NORTH AMERICA AND AN UPPER
LOW OVER HUDSON BAY WILL KEEP NORTHWEST FLOW OVER THE UPPER GREAT
LAKES REGION FOR MUCH OF THE LONG TERM PERIOD. THIS WILL LEAD TO
SEVERAL SHORTWAVES DROPPING SOUTHEAST ACROSS THE REGION...WHILE THE
UPPER LOW OVER HUDSON BAY GRADUALLY SINKS SOUTH TOWARDS THE AREA.
THUS...EXPECT GRADUALLY COOLING TEMPERATURES THROUGH EARLY NEXT
WEEK.

THREE PIECES OF ENERGY WITHIN THE LARGER SHORTWAVE TROUGH MOVING
THROUGH THE UPPER GREAT LAKES REGION WEDNESDAY NIGHT AND THURSDAY
WILL BE DRIVING THE WEATHER FOR THE START OF THE LONG TERM PERIOD.
THE SOUTHERN TWO WAVES WILL BE SUPPORTING THE SURFACE LOW MOVING
THROUGH SOUTHERN WISCONSIN AND THE INVERTED TROUGH CROSSING THE
UPPER GREAT LAKES REGION. AT THE START OF THE LONG TERM
PERIOD...EXPECT THE HEAVIEST PRECIPITATION TO BE ONGOING OVER
NORTHERN ONTARIO AND FAR NORTHERN LAKE SUPERIOR...WHILE THERE WILL
BE SOME SNOW OVER EASTERN UPPER MICHIGAN TIED TO THE NOSE OF THE
850-700MB WARM AIR ADVECTION INTERACTING WITH THE DEEPER MOISTURE.
THINKING MUCH OF THE REST OF THE AREA WILL BE SEEING LIMITED
PRECIPITATION CHANCES WITH THE POCKET OF DRY AIR BETWEEN 925-750MB.
THEN AS THE 850-700MB TROUGH SWEEPS SOUTHEAST THROUGH THE AREA
THROUGH THE NIGHT...EXPECT SNOW TO QUICKLY SPREAD INTO THE AREA
THROUGH THE EVENING/OVERNIGHT HOURS. WITH THAT INITIAL PRECIPITATION
STAYING TO THE NORTH OF THE LAND AREA INITIALLY...HAVE TRENDED
QPF/SNOW AMOUNTS DOWN SLIGHTLY OVER THE WEST/CENTRAL (1-2IN).
NORTHEAST OF A LINE FROM HOUGHTON TO MANISTIQUE...HAVE AMOUNTS IN
THE 2-3.5 INCH RANGE AND WILL CONTINUE TO MENTION IN THE HWO FOR
THOSE AREAS. AS THE DEEPER MOISTURE DEPARTS THURSDAY
MORNING...WILL SEE THE SNOW DIMINISH...BUT THINK THERE WILL BE
ENOUGH TERRAIN INFLUENCE TO HELP KEEP SNOW SHOWERS IN THE
NORTH-NORTHWESTERLY WIND SNOW BELTS UNTIL THE COLD AIR ARRIVES
THURSDAY AFTERNOON AND INCREASES DELTA-T VALUES TOWARDS THE LOW 20S
BY THURSDAY EVENING. THERE ARE HINTS OF LIMITED ICE CRYSTALS (AND
THUS FREEZING DRIZZLE) OVER THE WEST AS THAT DEEP MOISTURE
DEPARTS...BUT THINK IT IS TOO MARGINAL TO MENTION AT THIS POINT.

WITH THAT COLD AIR ARRIVING FROM NORTHWEST TO SOUTHEAST ON THURSDAY
AFTERNOON/EVENING...SHOULD SEE LAKE EFFECT COVERAGE INCREASING
DURING THAT TIME FRAME. WILL TREND POPS UP TO LIKELY/DEFINITE VALUES
FOR THE FAVORED NORTHWEST WIND SNOW BELTS FOR THURSDAY NIGHT. WHILE
SNOW IS EXPECTED...THERE ARE A COUPLE LIMITING FACTORS FOR HIGHER
SNOWFALL AMOUNTS. FIRST...THE APPROACHING HIGH PRESSURE RIDGE WILL
KEEP THE SUBSIDENCE INVERSION AROUND 5KFT THROUGH THE PERIOD. WHILE
MUCH OF THE CLOUD WILL BE IN OR JUST ABOVE THE DGZ...THINK THE
FRACTURING OF THE FLAKES FROM THE GUSTY WINDS WILL KEEP SNOW RATIOS
LOWER (BUT BE BETTER AT REDUCING VISIBILITIES). THUS...HAVE
SNOWFALL AMOUNTS OF 1-4 INCHES IN THE FAVORED SNOW BELTS DURING THAT
PERIOD. AS THE HIGH MOVES JUST SOUTH OF THE AREA ON FRIDAY...EXPECT
WINDS TO BACK TOWARDS THE WEST AND LOWER THE SUBSIDENCE INVERSION
TOWARDS 4KFT. THEREFORE...WILL GRADUALLY DIMINISH PRECIPITATION
CHANCES THROUGH FRIDAY AS WINDS BACK TO THE SOUTHWEST ON FRIDAY
NIGHT.

THE NEXT CLIPPER WILL SWEEP ACROSS THE AREA SATURDAY AND DRAG A WEAK
SURFACE TROUGH WITH IT. STILL SOME DIFFERENCES IN THE TIMING WITH
THIS FEATURE...SO WILL GO WITH LOW END CHANCE POPS SPREADING ACROSS
THE CWA ON SATURDAY. OVERALL...LOOKS LIKE JUST A QUICK DUSTING OF
SNOW WITH THIS FEATURE. BEHIND THE TROUGH...COLD AIR WILL FILTER
BACK INTO THE UPPER GREAT LAKES REGION AND BRING ANOTHER PERIOD OF
LAKE EFFECT FOR THE NORTH-NORTHWEST WIND SNOWBELTS. ONCE AGAIN...THE
HIGH PRESSURE RIDGE NOSING EAST INTO THE AREA WILL KEEP THE
SUBSIDENCE INVERSION AROUND 5KFT AND KEEP THE LAKE EFFECT AMOUNTS ON
THE LIGHT SIDE. ONE ITEM TO WATCH IS THE POTENTIAL FOR A WEAK
SHORTWAVE SLIDING ACROSS THE AREA ON MONDAY. THERE ARE HINTS THAT
THIS MAY RAISE INVERSION HEIGHTS TOWARDS 7-10KFT...WHICH WOULD
PROVIDE THE POTENTIAL FOR MODERATE LAKE EFFECT. WHEN THAT
OCCURS...WITH ANOTHER SURGE OF COLD AIR (850MB TEMPS FALLING TO THE
MID -20S) THE CLOUD WILL BE WELL ABOVE THE DGZ AND SUPPORT SMALL
FLAKES THAT ARE HIGHLY EFFICIENT AT REDUCING VISIBILITY. WITH THE
HIGH MOVING SOUTHEAST FROM THE NORTHERN PLAINS ON MONDAY MORNING TO
THE OHIO RIVER VALLEY ON TUESDAY...EXPECT GRADUALLY BACKING WINDS
OVER LAKE SUPERIOR AND WILL FOLLOW THAT IDEA FOR AT LEAST LIKELY
POPS FOR THE FAVORED WIND DIRECTIONS THROUGH TUESDAY (WINDS NEAR
WESTERLY BY TUESDAY EVENING). WON/T MENTION IN THE HWO AT THIS
POINT...AS AMOUNTS WILL BE ON THE LOW SIDE...BUT MAY NEED TO ADDRESS
THE END OF THE WEEK LAKE EFFECT AND THE SUN-TUE LAKE EFFECT IN THE
FUTURE DUE TO THE LIKELY LOW VISIBILITIES IN THE STRONGER BANDS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM EST TUE JAN 27 2015

LINGERING LOW CLOUDS WILL BE SLOW TO EXIT OVER MUCH OF THE W HALF OF
UPPER MI THIS AFTN/EVENING UNDER LIGHT WIND FIELDS. AT KIWD/KSAW...
MVFR CIGS ARE LIKELY TO LINGER INTO THE EVENING. SLIGHT
STRENGTHENING OF DOWNSLOPE WIND SHOULD ALLOW MVFR CIGS TO SCATTER
OUT AT KIWD LATE THIS EVENING. IT MAY NOT BE UNTIL OVERNIGHT THAT
MVFR CIGS SCATTER OUT AT KSAW. RECENT VIS SATELLITE IMAGERY SHOWS
GRADUAL EXPANSION OF LOWER CLOUDS TOWARD KCMX. SO...IT APPEARS MVFR
CIGS WILL LIKELY DEVELOP AT KCMX IN THE NEXT COUPLE OF HRS...AND
THEN LINGER THRU THE EVENING. VFR CONDITIONS SHOULD BE THE RULE AT
ALL TERMINALS LATE TONIGHT THRU WED MORNING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 AM EST TUE JAN 27 2015

EXPECT S TO SW WINDS UNDER 20 KTS TO DOMINATE THRU WED AS A HI PRES
RIDGE OVER UPPER MI TODAY SINKS SLOWLY INTO THE LOWER GREAT LAKES.
ON THE NORTHERN FLANK OF A HI PRES RIDGE ORIENTED ACROSS THE CENTRAL
GREAT LAKES. LO PRES WILL THEN TRACK FROM THE MID MISSISSIPPI VALLEY
WED NIGHT TO THE LOWER LAKES THU NIGHT. BEHIND THE LOW...N TO NW
WINDS WILL INCREASE TO 20-30KT AND THEN TO GALE FORCE LATE THU AND
THU NIGHT. SINCE THESE STRONG WINDS WILL DRAW MUCH COLDER ARCTIC AIR
INTO THE UPPER LAKES...HEAVY FREEZING SPRAY WILL DEVELOP OVER MUCH
OF THE LAKE AND CONTINUE INTO FRI...WHEN WINDS/WAVES WILL DIMINISH
WITH THE CLOSER APPROACH OF CANADIAN HI PRES. ANOTHER DISTURBANCE
AND COLD FRONT MAY SWING ACROSS THE UPPER LAKES ON SAT.
&&

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

$$

SHORT TERM...KC
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...KC


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