Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 210040
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
840 PM EDT SUN JUL 20 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 442 PM EDT SUN JUL 20 2014

UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE OVER THE SOUTHERN
ROCKIES AND A BROAD 500 MB TROUGH ACROSS THE EASTERN U.S. AND
ANOTHER OVER WESTERN CANADA. THE RIDGE BUILDS TO THE NORTH THIS
FORECAST PERIOD WITH THE UPPER GREAT LAKES GETTING INTO THE
PERIPHERY OF THE RIDGE AND NEAR THE WESTERLIES FOR THIS FORECAST
PERIOD. THIS MAKES THE FORECAST A BIT MORE DIFFICULT BECAUSE OF THE
RING OF FIRE SCENARIO AND ANY LITTLE SHORTWAVE COULD SET OFF
CONVECTION. LOOKS LIKE THROUGH MONDAY THAT THE AREA WILL BE ON THE
SOUTHERN PERIPHERY OF SHORTWAVES PASSING BY WELL TO THE NORTH OF THE
AREA UNTIL A STRONGER SHORTWAVE TOPS THE RIDGE AND AFFECTS THE AREA
MON NIGHT.

NAM SHOWS SOME WEAK 850-500 MB Q-VECTOR CONVERGENCE THROUGH MON WITH
MAJORITY OF MOISTURE REMAINING NORTH OF THE AREA. WILL NOT MAKE MANY
CHANGES TO THE GOING FORECAST. WILL KEEP IT DRY THROUGH THIS
EVENING...THEN HAVE SOME SLIGHT CHANCE TO CHANCE POPS ACROSS THE
NORTHERN CWA LATE TONIGHT AS LEFTOVER CONVECTION FROM MN TRIES TO
MOVE THROUGH AND GIVE THE KEWEENAW MAINLY A GLANCING BLOW. ENOUGH
UNCERTAINTY AGAIN FOR MON AFTERNOON TO HAVE SOME SLIGHT CHANCE POPS
ACROSS THE NORTHERN HALF OF THE CWA. OVERALL DID NOT MAKE TOO MANY
CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER. MADE A
FEW MINOR TWEAKS TO TEMPERATURES UPWARD FOR SOME DOWNSLOPE AREAS FOR
LOWS TONIGHT AND HIGHS ON MONDAY.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 442 PM EDT SUN JUL 20 2014

MONDAY NIGHT INTO TUESDAY UPPER MI WILL BE SANDWICHED IN A WEAK
TROUGH BETWEEN TWO SURFACE HIGH PRESSURE CENTERS...ONE OVER THE MID
ATLANTIC AND THE OTHER OVER THE CANADIAN PRAIRIES. ALOFT...STRONG
HIGH PRESSURE IS ANCHORED OVER NEW MEXICO AND THE MID ATLANTIC...AND
LOW PRESSURE IS SITUATED OVER HUDSON BAY. AS A RESULT...500MB FLOW
OVER THE NORTHERN PLAINS AND UPPER MI IS SOMEWHAT ZONAL. A POTENT
SHORTWAVE WILL KICK OFF CONVECTION IN THE NORTHERN PLAINS BY LATE
MONDAY AFTERNOON. THIS CONVECTIVE COMPLEX WILL BE THE MAIN FEATURE
OF INTEREST FOR THE LONG TERM FORECAST.

HAVE LIKELY TO CATEGORICAL POPS THROUGH THE CWA MONDAY NIGHT INTO
TUESDAY. MUCAPE VALUES SHOW EXTREME INSTABILITY BY U.P. STANDARDS
ACROSS THE WESTERN U.P. MONDAY EVENING /00Z TUE. MUCAPE VALUES ARE
FORECAST TO BE UPWARDS OF 3000 J/KG...AND MORE LIKE 1000 J/KG IN THE
EAST. THIS IS CONDITIONAL THOUGH...GIVEN THE ENVIRONMENT WILL BE
LARGELY CAPPED WITH THE RIDGE IN PLACE. HOWEVER...ISENTROPIC ASCENT
ON THE 315K SFC AHEAD OF THE DEVELOPING SURFACE LOW...AND A 25 TO 35
KNOT LL JET OVER SOUTHERN MN/WESTERN WI/IOWA WILL SUPPORT AN
ENVIRONMENT FAVORABLE FOR SUSTAINING ANY INCOMING MCS AND FOR
DEVELOPING ELEVATED CONVECTION AFTER 00Z TUE. 0-6 KM/1-6KM SHEAR IS
FAVORABLE FOR MCS SUSTAINABILITY/TSTORMS DEVELOPMENT AS
WELL...AROUND 25-40 KNOTS THROUGH MUCH OF TUESDAY. WITH A SHALLOW
STABLE LAYER AT THE SURFACE...THINKING SOME SEVERE LEVEL WIND GUSTS
AND HAIL ARE A SIGNIFICANT POSSIBILITY. THE BEST CHANCES WILL BE
OVERNIGHT MONDAY AND THROUGH EARLY TUESDAY MORNING ACROSS THE WEST
AND CENTRAL. AS FAR AS TIMING GOES...EXPECT SHOWERS/STORMS TO MOVE
IN/DEVELOP LATE MONDAY EVENING /3Z/ OUT WEST...AND CONTINUE TO MOVE
EASTWARD THROUGH TUESDAY...THOUGH SEVERE POTENTIAL DIMINISHES AS
THINGS PROGRESS EASTWARD. GENERALLY THE BETTER INSTABILITY
DIMINISHES AND BECOMES LARGELY CONFINED TO THE WEST/CENTRAL U.P./WI
BORDER THROUGHOUT THE DAY...AND THE UPPER LEVEL SUPPORT DIMINISHES
AS THE LOW EXITS THE AREA.

LARGE SCALE RIDGING EXTENDING FROM THE HIGH PRESSURE CENTERED OVER
NEW MEXICO WILL SHIFT SLIGHTLY EASTWARD INTO THE MIDWEST...ALLOWING
SURFACE HIGH PRESSURE TO INFILTRATE UPPER MICHIGAN FOR WEDNESDAY
AFTERNOON AND THURSDAY. THIS WILL BRING A COOL DOWN AND DRIER
CONDITIONS TO THE REGION...ESPECIALLY WEDNESDAY WITH NORTHERLY WINDS
OFF LAKE SUPERIOR. 850MB TEMPS WILL BE AROUND 7-10C...SO EXPECT HIGH
TEMPERATURES IN THE 60S AND 70S.

AN UPPER LEVEL LOW WILL MOVE FROM ALBERTA INTO ONTARIO OVER THE
WEEKEND...BRINGING UNSETTLED WEATHER BACK TO THE GREAT LAKES THIS
WEEKEND AND FOR THE START OF NEXT WEEK. HAVE KEPT CHANCE
SHOWERS/TSTORMS FOR NOW. TEMPS LOOK SEASONABLE...WITH HIGHS IN THE
UPPER 60S AND 70S.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 839 PM EDT SUN JUL 20 2014

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS FCST PERIOD AT
ALL SITES. THE REMNANTS OF SHRA/TSRA DEVELOPING IN NRN MN LATE THIS
EVENING MAY REACH NW UPPER MI LATE TONIGHT AT CMX. SINCE THE
PROBABILITY/CONFIDENCE IS LOW...IT WAS NOT MENTIONED IN THE TAF AT
THIS TIME.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 PM EDT SUN JUL 20 2014

SOUTHERLY WINDS WILL PREVAIL OVER MOST OF LAKE SUPERIOR THRU MON. A
LOW PRESSURE SYSTEM WILL FINALLY CROSS THE UPPER LAKES
TUE...BRINGING A WIND SHIFT TO THE N. WINDS THRU THE FCST PERIOD
WILL GENERALLY BE UNDER 20 KNOTS. HOWEVER...THERE WILL BE OCNL
PERIODS OF STRONGER WINDS (15-30KT) AT THE HIGHER OBS PLATFORMS.
THESE STRONGER WINDS WILL AFFECT MAINLY THE E HALF OF LAKE
SUPERIOR...PARTICULARLY STANNARD ROCK TONIGHT. FOG SHOULD SLOWLY
DEVELOP/EXPAND OVER THE LAKE...ESPECIALLY AFTER ANY PCPN OCCURS.
&&

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

$$

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





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