Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 181859
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
259 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 THROUGH FRIDAY)
ISSUED AT 247 AM EDT SAT APR 18 2015

NAM SHOWS TWO 500 MB TROUGHS WITH THE SOUTHERN ONE OVER THE CENTRAL
PLAINS AND THE NORTHERN ONE OVER THE NORTHERN PLAINS 12Z SUN. THE
SOUTHERN TROUGH GETS ABSORBED INTO THE NORTHERN TROUGH WHICH HELPS
TO SLOW DOWN THE EASTWARD MOVEMENT OF THE NORTHERN SYSTEM. THE
TROUGH CONTINUES TO SLOWLY MOVE INTO THE UPPER GREAT LAKES WHERE A
500 MB LOW MOVES INTO LAKE SUPERIOR MON NIGHT. NAM SHOWS SOME DEEPER
MOISTURE AND 850-500 MB Q-VECTOR CONVERGENCE MOVING IN SUN INTO SUN
NIGHT. LOOKS LIKE THERE COULD BE A DRY SLOT MOVING THROUGH ON MONDAY
ACROSS THE CENTRAL CWA AND HAVE LOWEST POPS THERE. DID REMOVE SNOW
FROM FORECAST FOR MONDAY AS LOOKED TOO WARM FOR IT TO OCCUR WITH
SYSTEM SLOWING DOWN A BIT AND COLDER AIR LAGGING...BUT KEPT IT IN
FOR MON NIGHT. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED 500
MB LOW AFFECTING THE UPPER GREAT LAKES 12Z TUE. THE TROUGH MOVES
SLOWLY EAST 12Z WED...BUT STILL AFFECTS THE UPPER GREAT LAKES ON WED
INTO FRI. THIS WILL MEAN COLD AND UNSETTLED WEATHER THIS FORECAST
PERIOD WITH TEMPERATURES REMAINING WELL BELOW NORMAL. WILL HAVE A
RAIN/SNOW POSSIBILITY FOR POPS FOR THIS PERIOD WITH SNOW
ACCUMULATIONS MINIMAL.
&&

.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...07
AVIATION...SRF
MARINE...SRF



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