Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KMQT 142329
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
729 PM EDT MON APR 14 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM EDT MON APR 14 2014

UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE UPPER
MISSISSIPPI RIVER VALLEY THIS MORNING AND THIS TROUGH WILL CONTINUE
TO HEAD EAST TONIGHT INTO THE UPPER GREAT LAKES AND INTO THE LOWER
GREAT LAKES BY TUE AFTERNOON. THE SHORTWAVE RESPONSIBLE FOR THE
HEAVY SNOW THIS MORNING WILL CONTINUE TO MOVE AWAY. NAM...GFS AND
ECMWF ALONG WITH THE CANADIAN BRING IN SOME WEAK 850-500 MB Q-VECTOR
CONVERGENCE THIS AFTERNOON AND THIS LASTS THROUGH TONIGHT BEFORE
MOVING OUT ON TUE.

LAKE EFFECT SNOW SHOWERS WILL CONTINUE THROUGH THIS FORECAST PERIOD
AS 850 MB TEMPERATURES ARE AROUND -16C AND WITH ALL THE ICE OUT ON
LAKE SUPERIOR...LAKE-850 MB DELTA-T IS 16C WHICH IS ENOUGH FOR LAKE
EFFECT. ANOTHER WEAK DISTURBANCE PASSES THROUGH TONIGHT INTO TUE AND
WITH ITS MOISTURE AND LIFT...THIS WOULD BE ENOUGH TO CONTINUE THE
LAKE EFFECT SNOW SHOWERS FOR NORTH TO NORTHWEST AFFECTED LAKE
SUPERIOR LAKE EFFECT SNOW BELTS. WILL NOT GET TOO OUT OF HAND THOUGH
AS ICE COVERAGE IS LIMITING THE INTENSITY A BIT. PUSHED POPS UP A
BIT IN THE LAKE EFFECT SNOW BELTS TO SCATTERED. TEMPERATURES LOOK TO
BE PRETTY COLD THIS FORECAST PERIOD AND WITH FRESH SNOW COVER AND
LIGHT WINDS TONIGHT...THE TEMPERATURES WILL DROP AND THERE COULD BE
A FEW RECORD LOW TEMPERATURES AROUND FOR LOWS AND MAYBE EVEN COLD
RECORD MAXIMUM TEMPERATURES FOR HIGHS ON TUE. OTHERWISE...DID NOT
MAKE TOO MANY CHANGES TO THE GOING FORECAST.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 429 PM EDT MON APR 14 2014

HIGH PRESSURE WILL BE OVER THE UPPER GREAT LAKES REGION ON TUESDAY
NIGHT AND LEAD TO THE CALM BEFORE THE NEXT SNOW STORM TO AFFECT THE
AREA WEDNESDAY INTO WEDNESDAY NIGHT. THE UPPER TROUGH ASSOCIATED
WITH THE COLDER TEMPERATURES EXPERIENCED TODAY AND TUESDAY WILL
SHIFT EAST...WHILE A SECONDARY TROUGH DIGS INTO THE DAKOTAS AND
MINNESOTA (PROVIDING THE SUPPORT FOR THE NEXT SYSTEM). THERE COULD
BE A FEW LINGERING SHOWERS OVER THE EASTERN CWA AS THE UPPER TROUGH
DEPARTS...BUT WOULD EXPECT A QUICK PERIOD OF CLEARING DURING THE
EVENING BEFORE THE MID-HIGH CLOUDS APPROACH AHEAD OF THE NEXT
SYSTEM.  THIS CLEARING SHOULD LEAD TO A QUICK COOL DOWN TO TEMPS
FOR INTERIOR LOCATIONS (SINGLE DIGITS ABOVE ZERO) AND THEN WARMING
LATE AS THE MID-HIGH CLOUDS ARRIVE.

THIS NEXT SYSTEM IS LOOKING TO BRING ANOTHER WIDESPREAD SNOWFALL TO
AT LEAST THE WESTERN HALF OF UPPER MICHIGAN...IF NOT THE ENTIRE
U.P. THE SURFACE LOW ITSELF ISN/T OVERLY STRONG AND ACTUALLY
WEAKENS FROM 997MB TO 1017MB AS IT MOVES FROM THE CENTRAL/NORTHERN
PLAINS ON TUESDAY EVENING TO NORTHERN LAKE MICHIGAN AT 12Z
THURSDAY. BUT THE STRONG LOW-MID LEVEL FORCING ALONG THE INVERTED
TROUGH THAT TRACKS AND PIVOTS THROUGH CENTRAL UPPER MICHIGAN WILL
LEAD TO MUCH OF THE PRECIPITATION. THE MODELS STILL VARY A LITTLE
ON WHERE THE INVERTED TROUGH IS LOCATED AND THE LOW TRACK...BUT THE
GENERAL CONSENSUS IS FOR AT LEAST THE WESTERN U.P. TO SEE MODERATE
TO HEAVY SNOWFALL WEDNESDAY INTO WEDNESDAY NIGHT. INITIAL PRECIP ON
WEDNESDAY WILL BE ASSOCIATED WITH THE STRONG WAA AND ISENTROPIC
ASCENT AS THE LOW/TROUGH APPROACH. THIS WILL LIKELY AFFECT MUCH OF
THE CWA...WITH THE HEAVIEST OVER THE WEST HALF. THEN AS THE SURFACE
TROUGH PIVOTS LATE WEDNESDAY AFTERNOON AND INTO THE NIGHT...THE
BETTER FORCING (850-700MB FGEN) AND PRECIP WILL FOCUS OVER THE
WESTERN THIRD OF THE CWA. IN ADDITION...THE WESTERN HIGHER TERRAIN
AREAS WILL LIKELY SEE UPSLOPE HELP TOO HEADING INTO THE OVERNIGHT
HOURS AS WINDS TURN TO MORE OF A NORTHERLY DIRECTION. THIS UPSLOPE
FORCING SHOULD KEEP SNOW GOING OVER THOSE LOCATIONS THROUGH THURSDAY
MORNING. FINALLY...DEPENDING ON THE EXACT TRACK OF THE
LOW/TROUGH...THERE IS THE POTENTIAL FOR SOME RAIN TO MIX WITH THE
SNOW OVER THE SOUTHEAST PART OF THE CWA.

AS FOR PRECIPITATION AMOUNTS...A GENERAL MODEL CONSENSUS GIVES A
DECENT SWATH OF 0.6-1.10 INCHES OVER THE WESTERN AREA...WITH THE
HIGHEST AMOUNTS FOCUSED WHERE THE STRONGER FGEN FEATURE SETS UP
(RIGHT NOW FROM SW TO NE ACROSS WESTERN UPPER MICHIGAN). 09Z SREF
PROBS OF 1IN OF QPF AROUND 30-50 PERCENT OVER THE WESTERN CWA AND
HAVE 12HR PROBS OF 0.5IN DURING THE DAY ON WEDNESDAY EXCEEDING 50
PERCENT. THUS...HAVE INCREASED THE GOING FORECAST BY 0.15-0.30 OVER
THE WEST WHERE THE GREATEST CONFIDENCE IN THE BEST FORCING IS.
FARTHER EAST...MUCH OF THE PRECIP WILL COME FROM THE WAA ON
WEDNESDAY AFTERNOON/EVENING AND KEEPS AMOUNTS IN THE 0.25-0.50 INCH
RANGE. SINCE COLD AIR WILL BE IN PLACE AND STRONG FORCING LIKELY
OCCURRING AROUND THE DGZ...THINK RATIOS OVER THE WESTERN HALF OF THE
CWA WILL BE IN THE 13-16 TO 1 RANGE AND THAT MATCHES UP WELL WITH
THE LATEST COBB OUTPUT. VALUES OVER THE CENTRAL MAY BE A LITTLE
LOWER HEADING LATER IN THE EVENT (WEDNESDAY NIGHT) AS WARMER AIR
MOVES NORTH INTO THE EASTERN CWA. THAT ALSO AFFECTS SOME OF THE
EASTERN AREAS...SINCE THE FORCING WILL FOCUS BELOW THE DGZ AND LEAD
TO SNOW RATIOS CLOSER TO 10-1. COMBINING QPF AND SNOW RATIOS...HAVE
THE HIGHEST AMOUNTS OVER WESTERN UPPER MICHIGAN AND GENERALLY IN
THE 6 TO 13 INCH RANGE THROUGH THURSDAY MORNING. THUS...OPTED TO
ISSUE A WINTER STORM WATCH FOR LOCATIONS ALONG AND WEST OF A LINE
FROM MARQUETTE/DICKINSON COUNTIES. FARTHER EAST...DELTA/ALGER MAY
BE BORDERLINE FOR WARNING AMOUNT SNOWFALL...BUT CONFIDENCE WAS TOO
LOW TO INCLUDE THEM IN THE WATCH. OTHERWISE...THE REST OF THE AREA
LOOKS TO SEE ADVISORY SNOWFALL...EXCEPT FAR SOUTHERN MENOMINEE
COUNTY WHERE THE INITIAL SNOW WILL STRUGGLE TO ACCUMULATE WITH
WARMING TEMPS BEFORE CHANGING TO RAIN.

THIS LOW WILL CONTINUE TO DISSIPATE ON THURSDAY AND DIMINISH THE
SNOWFALL ACROSS THE AREA. A HIGH PRESSURE RIDGE (FROM A HIGH IN FAR
NORTHWEST ONTARIO) SHOULD LEAD TO A DRY/CALM NIGHT ON THURSDAY
NIGHT OVER THE NORTHWEST TWO-THIRDS OF THE CWA. WITH A FRESH
SNOWFALL...WOULD THINK RADIATIONAL COOLING WILL BE MAXIMIZED
(ESPECIALLY OVER THE NORTHWESTERN CWA) AND MAY NEED TO TREND LOWS
DOWN A LITTLE FURTHER THAN THE GOING FORECAST OF LOWER 20S.

MODELS CONTINUE TO DIFFER ON THE HANDLING OF THE UPPER LEVEL
DISTURBANCE FOR THIS WEEKEND...BUT SEEM TO BE COMING INTO A LITTLE
BETTER AGREEMENT WITH THE UPPER TROUGH TRACKING FROM THE CENTRAL
PLAINS THURSDAY NIGHT AND THROUGH THE CENTRAL/LOWER GREAT LAKES ON
SATURDAY. THE LINGERING TROUGH (LIKELY AROUND NORTHERN LAKE
MICHIGAN) WILL BE THE INITIAL FOCUS FOR PRECIPITATION AS THE LOW
MOVES TOWARDS THE GREAT LAKES REGION BEFORE TRENDING CLOSER TO
THE LOW TRACK. TO THE NORTHWEST OF THE LOW...CANADIAN HIGH PRESSURE
CENTERED NEAR JAMES BAY WILL STRETCH A RIDGE SOUTHWEST INTO
NORTHERN MINNESOTA AND WESTERN LAKE SUPERIOR. WITH THAT IDEA...WILL
KEEP CHANCE POPS FOR SNOW CONFINED TO THE SOUTHEAST HALF OF THE CWA
FRIDAY THROUGH SATURDAY...ALTHOUGH MAY NEED TO TREND TO A SHARPER
CUTOFF TO THE NORTHWEST WITH THE LATEST MODEL TRENDS. THE RIDGE WILL
THEN ARRIVE BEHIND THE LOW AND PRODUCE DRY CONDITIONS FOR SATURDAY
NIGHT AND THE FIRST PART OF SUNDAY. ANOTHER SHORTWAVE LOOKS TO MOVE
THROUGH SUNDAY INTO SUNDAY NIGHT FROM THE WEST-NORTHWEST BUT DRY AIR
REMAINING FROM THE HIGH WILL LIKELY KEEP PRECIP CHANCES LIMITED.

AFTER A WEEK OF BELOW NORMAL TEMPERATURES...MODELS ARE INDICATING A
TRANSITION TO A MORE ZONAL FLOW PATTERN OVER THE NORTHERN CONUS FOR
NEXT WEEK. THIS SHOULD ALLOW TEMPERATURES TO RETURN TO MORE NORMAL
VALUES FOR THIS TIME OF YEAR AND START THE SNOW MELT AGAIN.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 728 PM EDT MON APR 14 2014

ARRIVAL OF AN AREA OF LLVL DRY AIR/WEAKER PRES GRADIENT/LOSS OF
DAYTIME MIXING WL RESULT IN VFR CONDITIONS AND DIMINISHING WINDS
THIS EVNG AT ALL 3 SITES. BUT LK EFFECT MVFR CLDS/SOME -SHSN WL
REDVLP AT IWD AND CMX TOWARD MIDNGT WITH NOCTURNAL COOLING FVRBL FOR
LK EFFECT -SHSN AND APRCH OF DISTURBANCE/MOISTER AIR IN NW ONTARIO.
DOWNSLOPE NATURE OF THE EXPECTED NNW FLOW AT SAW SHOULD RESULT IN
CONTINUED VFR CONDITIONS THERE. APRCH OF HI PRES RDG/DAYTIME HEATING
THAT DISRUPTS THE LES PROCESS THIS LATE IN THE SEASON SHOULD BRING A
RETURN OF VFR WX AT IWD/CMX ON TUE AFTN.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 322 PM EDT MON APR 14 2014

NORTH GALES 35-40 KNOTS FOR TODAY...MAINLY EAST HALF...AS LOW
PRESSURE SYSTEM TRACKS ACROSS LOWER MICHIGAN THIS MORNING AND
EVENTUALLY ACROSS QUEBEC BY THIS EVENING. WINDS QUICKLY DIMINISH
BY THIS EVENING AND SHOULD REMAIN BLO 20 KTS OVER MOST OF THE LAKE
THROUGH TUESDAY. LOW PRESSURE SYSTEM LIFTING ACROSS UPPER GREAT
LAKES LATER ON WEDNESDAY WILL RESULT IN EAST TO NORTHEAST WINDS UP
TO 25 KTS OVER MAINLY WESTERN LAKE INTO THURSDAY. WINDS DIMINISH TO
LESS THAN 20 KTS REST OF THE FORECAST PERIOD.
&&

.HYDROLOGY...
ISSUED AT 429 PM EDT MON APR 14 2014

REPORTS OF ICE JAMS IN DELTA COUNTY SUNDAY ON ESCANABA RIVER AND
ASSOCIATED TRIBUTARIES. WITH COLDER TEMPERATURES OVER THE NEXT COUPLE
OF DAYS...EXPECT LOWER RUNOFF OF MELTING SNOW TO REDUCE THE POTENTIAL
FOR ICE JAMS THIS WEEK. WIDESPREAD PRECIPITATION IS IN THE FORECAST
FOR WEDNESDAY THROUGH THURSDAY AND THERE IS THE POTENTIAL FOR AN
ADDITIONAL INCH OF LIQUID EQUIVALENT PRECIPITATION OVER WESTERN UPPER
MICHIGAN. THIS PRECIP ADDED TO EXISTING SNOWPACK WITH WATER
EQUIVALENT OF 4-9 INCHES OVER MAINLY WESTERN UPPER MICHIGAN WILL
RESULT IN ANOTHER PERIOD OF SNOWMELT AND RUNOFF ONCE WARMER
TEMPERATURES MOVE BACK INTO THE REGION NEXT WEEK.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
     MORNING FOR MIZ001>005-009>011-084.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...07
LONG TERM...SRF
AVIATION...KC
MARINE...07
HYDROLOGY...SRF




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.