Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 190704
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
304 AM EDT SUN APR 19 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 304 AM EDT SUN APR 19 2015

UPPER AIR PATTERN CONSISTS OF A 500 MB LOW OVER EASTERN CO THIS
MORNING IN AN EMBEDDED TROUGH AND ANOTHER TROUGH OVER THE NORTHERN
PLAINS. BOTH TROUGHS HEAD SLOWLY EAST WITH THE SOUTHERN ONE GETTING
ABSORBED INTO THE NORTHERN ONE TONIGHT WHILE THE NORTHERN TROUGH
ONLY MAKES IT TO THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT.

NAM TAKES SOME DEEPER MOISTURE AND 850-500 MB Q-VECTOR CONVERGENCE
AND MOVES IT ACROSS THE WESTERN CWA TODAY WHILE KEEPING THE EAST
HALF DRY BEFORE DEEPER MOISTURE AND STRONGER Q-VECTOR CONVERGENCE
MOVES IN TONIGHT ACROSS THE WHOLE CWA. THE LOW LEVEL ISENTROPIC
SURFACES OF I290K FOR THE NAM AND GFS SHOW THE STORY WITH DRY
SOUTHEAST FLOW PREVENTING THE EASTWARD ADVANCE OF PCPN FOR TODAY
ACROSS THE EAST HALF OF THE CWA AND WILL GO WITH A DRY FORECAST.
MODELS WERE HINTING AT THIS YESTERDAY WITH DRYING THE EAST OUT AND
WILL GO WITH THIS SCENARIO TODAY AND CONFINE POPS TO THE WEST HALF
OF THE CWA WITH THE HIGHEST POPS IN THE FAR WEST. LOOKS LIKE THERE
WILL BE A SHORTWAVE THAT MOVES IN AND AFFECTS MAINLY THE EASTERN
HALF OF THE CWA TONIGHT AND WILL HAVE HIGHEST POPS THERE WITH LIKELY
POPS IN THE WEST HALF. SOME OF THE COMPUTER MODELS WERE PUTTING OUT
SOME QPF THIS AFTERNOON OVER THE EASTERN HALF OF THE CWA...BUT WILL
GO WITH A DRY AIR SCENARIO PREVENTING ANYTHING FROM HITTING THE
GROUND AND AT MOST WILL SEE VIRGA IF EVEN THAT OVER THE EASTERN HALF
OF THE CWA. LOOKED TOO WARM FOR SNOW AND KEPT OUT OF THE FORECAST
FOR TONIGHT AS TRANSITION AND COLD AIR ARRIVE MON MORNING.
OVERALL...SLOWED EASTWARD PROGRESSION OF POPS DOWN AND KEPT
TEMPERATURES PRETTY MUCH THE SAME AS SOUTHEAST WINDS ARE NOT A REAL
WARM WIND.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 458 PM EDT SAT APR 18 2015

THE PATTERN WILL UNDERGO A TRANSITION TOWARD COLDER AND MORE
UNSETTLED WEATHER AS THE NRN AND SRN STREAMS PHASE LEAVING A
MID/UPPER LEVEL TROUGH OVER THE GREAT LAKES THROUGH MUCH OF THE
WEEK. THE TROUGH SHOULD FINALLY SHIFT INTO ERN CANADA AND NEW
ENGLAND BY THE WEEKEND LEAVING NW FLOW IN PLACE WITH CONTINUED BELOW
NORMAL TEMPERATURES.

SUN NIGHT...THE MODELS HAVE TRENDED FARTHER EAST WITH THE SHORTWAVE
LIFTING NNE FROM THE LOWER MS VALLEY TO THE GREAT LAKES AND THE
ASSOCIATED SFC-700 MB CIRCULATION. SO...THE STRONGER 300K ISENTROPIC
LIFT WOULD MAINLY BRUSH THE ERN CWA. HOWEVER...A BAND OF PCPN WITH
800-600 MB FGEN AHEAD OF THE NRN STREAM MID LEVEL TROUGH IS EXPECTED
TO GRADUALLY PUSH ACROSS THE WRN HALF OF UPPER MICHIGAN.
LIKELY/CATEGORICAL POPS STILL ARE ON TRACK EVEN IF THE QPF AMOUNTS
ARE NOT AS HIGH.

MON...THE PCPN IS EXPECTED TO DIMINISH AND COLDER AIR WILL SPREAD
THROUGH THE REGION AS THE MID LEVEL LOW ONLY SLOWLY MOVES TOWARD NW
LAKE SUPERIOR. THERE MAY BE A PERIOD WHERE THE RAIN COULD BRIEFLY
MIX WITH SNOW OVER THE HIGHER TERRAIN IN THE WEST HALF.
OTHERWISE...PCPN WILL DIMINISH OR END INTO THE AFTERNOON AS THE DRY
SLOT SPREADS ACROSS THE AREA.

MON NIGHT INTO TUE...MODELS SUGGEST THAT THE MID LEVEL LOW WILL
SLOWLY WOBBLE INTO THE NRN GREAT LAKES. WITH THE COMBINATION OF DEEP
MOISTURE AND WEAK SHORTWAVES NEAR THE LOW...EXPECT INCREASING PCPN
CHANCES AS MAINLY SNOW...PER FCST SOUNDINGS. THERE MAY BE SOME
ADDITIONAL ENHANCEMENT INTO THE HIGHER TERRAIN OVER THE WEST WITH
UPSLOPE WNW FLOW. A LIGHT COATING OF SNOW UP TO AN INCH MAY BE
POSSIBLE...MAINLY ON GRASSY SURFACES. DAYTIME WARMING TUE MAY
ENHANCE THE PCPN OVER INLAND AREAS WITH STEEP SFC-700MB LAPSE RATES
DEVELOPING. WITH TEMPS CLIMBING TO AROUND 40F...THE PCPN MAY MIX
WITH RAIN OVER THE SE HALF OF THE CWA.

WED-THU...THE LARGE COLD MID-LEVEL LOW IS FCST TO BE CENTERED OVER
OR NEAR THE GREAT LAKES THROUGH THU. COLD AIR ALOFT/SPRING DAYTIME
HEATING AND POTENTIAL OF SHORTWAVES ROTATING THROUGH THE AREA WITHIN
THE LARGE MID-LEVEL LOW CIRCULATION FAVORS AT LEAST SCT SHOWERY
PCPN... MOSTLY AS SNOW BUT POSSIBLY MIXING WITH RAIN SOUTH DURING
PEAK HEATING. THE BEST COVERAGE SHOULD BE IN THE AFTERNOON INLAND
FROM LAKE SUPERIOR WHERE HEATING WILL BE STRONGEST. HIGH TEMPS BOTH
DAYS SHOULD BE WELL BELOW NORMAL...IN THE MID 30S TO LOWER
40S...WARMEST S CNTRL.

FRI-SAT...AS THE MID LEVEL LOW SHIFTS TO THE EAST...TEMPERATURES
WILL GRADUALLY MODERATE AND PCPN CHANCES WILL DIMINISH.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 108 AM EDT SUN APR 19 2015

VFR CONDITIONS ARE EXPECTED AT KIWD/KCMX/KSAW THRU THIS AFTN AS LOW-
LEVEL SE WINDS EMANATING FROM DEPARTING HIGH PRES WORK TO KEEP DRIER
AIR IN PLACE. TIGHTENING PRES GRADIENT BTWN THE DEPARTING HIGH AND
LOW PRES OVER THE PLAINS WILL RESULT IN LLWS AT ALL TERMINALS
OVERNIGHT. LATEST KMQT VAD WIND PROFILE SHOWS A SE WIND OF 40KT AT
500FT AGL. MEANWHILE...DISTURBANCES WILL BE LIFTING NNE TOWARD THE
AREA. THE FIRST WAVE OF SCT -SHRA SHOULD REACH KIWD EARLY THIS
MORNING AND KCMX AROUND MID MORNING. WITH PCPN EXPECTED TO BE
LIGHT...VFR CONDITIONS WILL CONTINUE DESPITE THE -SHRA. THIS EVENING
HOWEVER...CIGS SHOULD FALL TO MVFR AT KIWD WITH PASSAGE OF SFC TROF
AND A WIND SHIFT TO AN UPSLOPE NW DIRECTION OFF LAKE SUPERIOR. AT
KSAW...VFR CONDITIONS WILL PREVAIL INTO THE EVENING HRS...AND THERE
MAY BE FEW -SHRA OR SPRINKLES FOR A TIME THIS AFTN.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 304 AM EDT SUN APR 19 2015

AS A LOW MOVES TOWARDS THE AREA TODAY...SOUTHEAST WINDS WILL BE ON
THE INCREASE AND WOULD EXPECT WINDS UP TO 30 KTS OVER THE EAST HALF
OF LAKE SUPERIOR WITH A FEW GALE FORCE GUSTS TO 35 KNOTS OVER THE
NORTHEASTERN PART OF LAKE SUPERIOR THIS AFTERNOON. ONCE THE LOW
BECOMES ESTABLISHED TO THE SOUTHWEST OF JAMES BAY MONDAY
NIGHT...EXPECT WEST TO NORTHWEST WINDS UP TO 25 KNOTS TO BE IN PLACE
THROUGH MUCH OF THE UPCOMING WORK WEEK.
&&

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

$$

SHORT TERM...07
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...07


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