Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 182102
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
502 PM EDT SAT APR 18 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 258 PM EDT SAT APR 18 2015

A 1026MB HIGH CENTERED OVER NORTHERN ONTARIO PLACED A RIDGE OVER
UPPER MICHIGAN AND LED TO ANOTHER DRY DAY IN THE UPPER GREAT LAKES.
NORTHEAST FLOW AROUND THIS RIDGE AND A SHALLOW POCKET OF MOISTURE
PRODUCED MVFR CLOUDS OVER PORTIONS OF WESTERN/CENTRAL UPPER MICHIGAN
THIS MORNING...BUT THEY HAVE SINCE MIXED OUT. THIS HAS LEFT THE U.P.
UNDER A MOSTLY SUNNY SKY...WITH THE ONLY CLOUDS BEING HIGH CLOUDS
MOVING IN FROM THE SOUTH AHEAD OF THE UPPER LOW IN COLORADO. THIS
UPPER LOW WILL MERGE WITH THE UPPER TROUGH DROPPING THROUGH THE
CANADIAN ROCKIES TO LEAD TO A MUCH COLDER PERIOD OVER THE UPPER
GREAT LAKES REGION OVER THE NEXT WEEK. BOTH OF THESE FEATURES LOOK
IMPRESSIVE ON WV IMAGERY...AND THEY HAVE A 1010MB SURFACE TROUGH
STRETCHING FROM CENTRAL SASKATCHEWAN TO EASTERN COLORADO.

WITH THE DRY AIR IN PLACE...WOULD EXPECT MUCH OF THE AREA TO REMAIN
DRY TONIGHT UNDER THE INCREASING MID-HIGH CLOUDS. THE BEST
OPPORTUNITY FOR RAIN WILL COME OVER THE FAR WEST AFTER THE MID LEVEL
RIDGE AXIS MOVES THROUGH...WHICH WILL BE ON THE EASTERN EDGE OF THE
WAVE AND MID LEVEL WARM AIR ADVECTION THAT MOVES NORTH THROUGH
MINNESOTA TONIGHT. WILL KEEP THE HIGHEST POPS OVER WESTERN LAKE
SUPERIOR AS THIS WAVE MOVES NORTH THROUGH MID MORNING WITH MAINLY
CHANCES OVER THE WESTERN THIRD OF THE U.P. AS THESE SHOWERS MOVE
THROUGH...THE INCREASING SOUTHERLY FLOW (900MB WINDS UP TO 45KTS
OVER THE WEST) COULD COMBINE WITH EXISTING DRY AIR TO EVAPORATING
SOME OF THE RAIN LATE TONIGHT INTO SUNDAY MORNING TO PRODUCE GUSTY
WINDS. SINCE IT IS CONDITIONAL ON RAIN...WON/T SHOW TOO HIGH OF
GUSTS IN THE GRIDS...BUT IT WILL BE SOMETHING TO KEEP AN EYE ON.

FOR THE REST OF THE DAY...EXPECT THE AREA TO BE UNDER MID CLOUDS AND
BROAD/WEAK WARM AIR ADVECTION. WILL CONTINUE TO MENTION SLIGHT TO
CHANCE POPS OVER THE WESTERN HALF OF THE CWA...BUT WITH THE MAIN
FORCING WELL TO THE WEST OF THE AREA (NEAR THE UPPER TROUGH AXIS IN
MANITOBA AND OVER THE RED RIVER VALLEY) AND THE EXISTING LOW LEVEL
DRY AIR...DON/T EXPECT THE PRECIPITATION TO BE ANYTHING SIGNIFICANT
AND MAY NOT EVEN OCCUR OVER THE CENTRAL U.P..  THE BEST OPPORTUNITY
FOR RAIN WILL COME LATE IN THE AFTERNOON AND MORE TOWARDS
EVENING...AS THE MID LEVEL TROUGH SHIFTS EAST TOWARDS THE AREA
(PUSHING THE BAND OF RAIN OVER WESTERN LAKE SUPERIOR EASTWARD) AND
BEGINS TO MERGE WITH THE SOUTHERN WAVE (STRENGTHENING/CONSOLIDATING
THE SURFACE LOW OVER THE AREA). WILL SHOW A RAMP UP TO THE POPS VERY
LATE IN THE SHORT TERM PERIOD OVER THE WEST THIRD WITH THAT
BAND.MODELS DIFFERING SOME ON THE LOCATION OF THE NEXT WAVE MOVING
NORTH THROUGH LOWER MICHIGAN LATE SUNDAY AFTERNOON AND WHERE THE
BEST 850-700MB WARM AIR ADVECTION AND PRECIP WILL OCCUR. WILL START
INTRODUCING SLIGHT CHANCES POPS TOWARDS EVENING...WITH THE BEST POPS
OCCURRING ON SUNDAY NIGHT.

.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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 116 PM EDT SAT APR 18 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. A HIGH PRESSURE
RIDGE CURRENTLY OVER THE AREA WILL DEPART TONIGHT AS SEVERAL
DISTURBANCES LIFT NORTH-NORTHEAST TOWARDS THE AREA. THINK THE FIRST
WAVE OF RAIN WILL MAINLY AFFECT KIWD AND POTENTIALLY KCMX LATE
TONIGHT INTO SUNDAY MORNING BEFORE SHIFTING TO THE NORTH OF THE
AREA. THIS WAVE WILL LEAD TO INCREASING MID/HIGH CLOUDS THROUGH THE
NIGHT...BUT AT THIS TIME DON/T THINK THE RAIN WILL BE STRONG ENOUGH
TO LOWER CEILINGS BELOW 4-5KFT. FINALLY...WILL CONTINUE TO MENTION
LLWS FOR THE WESTERN TAF SITES...AS WINDS AT 2KFT ARE AROUND
35-40KTS. IT DOES APPEAR TO BE MARGINAL...SINCE WINDS WILL BE
INCREASING THROUGH THE NIGHT...BUT THOUGHT IT WAS WORTH MENTIONING.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 PM EDT SAT APR 18 2015

A HIGH PRESSURE RIDGE WILL DEPART THE REGION TONIGHT AHEAD OF A
BROAD LOW THAT WILL BE THROUGH THE AREA LATE SUNDAY INTO MONDAY
NORTHEAST WINDS FUNNELING DOWN THE WESTERN SHORELINE OF LAKE
SUPERIOR WILL LEAD TO GUSTS TO 30KTS TOWARDS DULUTH. THEN AS THE
LOW MOVES TOWARDS THE AREA ON SUNDAY...SOUTHEAST WINDS WILL BE ON
THE INCREASE AND WOULD EXPECT GUSTS TO 30KTS OVER NORTHERN LAKE
SUPERIOR. 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...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF


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