Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 192024
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
424 PM EDT SAT JUL 19 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 424 PM EDT SAT JUL 19 2014

A FEW SPRINKLES/LIGHT SHOWERS ARE TRYING TO POP UP OVER WESTERN LAKE
SUPERIOR AHEAD OF THE SOUTHERN EDGE OF THE UPPER TROUGH OVER NW
ONTARIO. THE VARIOUS HIGH RES GUIDANCE SUGGEST A LITTLE MORE
DEVELOPMENT OVER WESTERN UPPER MICHIGAN LATE THIS AFTERNOON INTO
THIS EVENING. THERE IS A SURGE OF LOWER 60S DWPTS MOVING INTO
WESTERN UPPER MI AHEAD OF THE TROUGH /PER THE 63 DEWPT AT
ASX/...WHICH SUPPORTS THE MODEST FORECAST INSTABILITY FROM THE NWP.
AS SUCH...HAVE OPTED TO MAINTAIN SLIGHT CHANCE/LOW CHANCE POPS OVER
THE WESTERN HALF LATE THIS AFTERNOON INTO THIS EVENING DESPITE THE
VERY DRY ATMOSPHERE BELOW 800 MB. OTHERWISE...A LIGHT SOUTHERLY
BREEZE WILL CONTINUE TONIGHT AND GIVEN THE VARIABLE CLOUD COVER AND
HIGHER DEW POINTS...EXPECT TEMPERATURES TO BE IN THE UPPER 50S AND
LOWER 60S...WITH THE HIGHEST READINGS IN THE DOWNSLOPE LOCATIONS
NEAR LAKE SUPERIOR.

ON SUNDAY...HEIGHTS START TO RISE ACROSS THE AREA AS THE RIDGE OVER
THE PLAINS BUILDS NORTHWARD. STRONG 850MB WARM ADVECTION COMMENCES
DURING THE DAY ON SUNDAY WHICH WILL ALLOW FOR 850MB TEMPS TO RISE TO
THE UPPER TEENS ACROSS THE WEST SUNDAY AFTERNOON. THIS WILL LEAD TO
AN INCREASING CAP AS AN EML SPREADS ACROSS THE AREA IN THE W-SW
FLOW. WITH ANY FORCING FROM THE UPPER WAVE OVER SASKATCHEWAN STAYING
WELL NORTH AND WEST OF THE AREA DURING THE DAY...WILL MAINTAIN A DRY
FORECAST FOR THE DAY...EXCEPT FOR AREAS ACROSS THE FAR WEST LATE IN
THE DAY WHEN WEAK MID LEVEL Q-VECTOR CONVERGENCE MOVES IN BY 00Z.
OTHERWISE...WITH CONTINUED SOUTHERLY FLOW AND WARMER 850MB
TEMPS...HAVE OPTED TO RAISE TEMPS IN THE AREA INTO THE 80S FOR THE
ENTIRE REGION EXCEPT NEAR LAKE MICHIGAN. AREAS NEAR LAKE SUPERIOR
WILL LIKELY SEE MID 80S DUE TO THE DOWNSLOPE COMPONENT.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 424 PM EDT SAT JUL 19 2014

HIGH PRESSURE WILL REMAIN ANCHORED OVER NEW MEXICO...KEEPING A RIDGE
OVER MUCH OF THE WESTERN UNITED STATES THROUGH THE LONG TERM.
MEANWHILE...A LOW PRESSURE SYSTEM WILL MOVE FROM NORTHERN MANITOBA
SUNDAY EVENING INTO HUDSON BAY BY MONDAY EVENING. THIS WILL DRAG A
WEAK TROUGH THROUGH THE NORTHERN PLAINS MONDAY...FIRING CONVECTION
ALONG THE PERIPHERY OF THE RIDGE BY LATE AFTERNOON. AS THE LOW
PRESSURE SYSTEM MOVES FROM HUDSON BAY MONDAY EVENING INTO
NORTHEASTERN QUEBEC THROUGH WEDNESDAY NIGHT...THE TROUGH WILL DEEPEN
AND COVER THE EASTERN SEABOARD.

THE FIRST CHANCE FOR PRECIPITATION ACROSS UPPER MI COMES SUNDAY
NIGHT INTO MONDAY...AS THE LOW CROSSES FROM MANITOBA INTO HUDSON
BAY. PRECIPITATION THAT DEVELOPS AHEAD OF THE FRONTAL BOUNDARY IN
THE NORTHERN PLAINS WILL CROSS INTO THE WESTERN U.P. EARLY MONDAY
MORNING. WITH RIDGING AND A STRONG CAP FROM WARM AIR ADVECTION ALOFT
OVERNIGHT IN PLACE OVER MUCH OF THE CWA...EXPECT PRECIPITATION TO
FIZZLE OUT AS THE BOUNDARY MOVES EASTWARD INTO THE ARROWHEAD OF
MINNESOTA...CONFINING ITSELF FURTHER NORTH OVER LAKE SUPERIOR. KEPT
ALL BUT LAKE SUPERIOR AND FAR WESTERN UPPER MI DRY THROUGH MID
AFTERNOON. A BOUNDARY SETS UP WEST TO EAST ACROSS THE CWA BY LATE
AFTERNOON...WITH THE TROUGH TRYING TO PROGRESS EASTWARD AND LOW
PRESSURE DEVELOPING TO THE SOUTHWEST OVER SOUTH DAKOTA/NEBRASKA
MOVING WARM AIR NORTHWARD. LAKE BREEZES WILL ALSO TRY TO DEVELOP
AROUND THIS TIME...FURTHER REINFORCING THE BOUNDARY. WHILE THERE IS
CAPPING IN PLACE AND SOMEWHAT DRIER AIR...FEEL THERE IS POTENTIAL
FOR SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG THE BOUNDARY. MUCAPE
VALUES REACH AS HIGH AS 3K-4K BY LATE AFTERNOON FOR SOME PLACES...SO
IF THE BOUNDARY PROVIDES ENOUGH LIFT TO BREAK THROUGH THE CAP
THUNDERSTORMS COULD POP UP. KEPT SLIGHT CHANCE IN THE FORECAST FOR
NOW WEST AND ALONG LAKE SUPERIOR.

WITH 850MB TEMPERATURES REACHING THE UPPER TEENS AND LOW 20S...AND
DOWNSLOPE SOUTHERLY WINDS FOR MANY LOCATIONS...EXPECT MORE JULY-LIKE
TEMPERATURES MONDAY. DEPENDING ON THE EXTENT OF CLOUD COVER WITH THE
APPROACHING TROUGH...HIGHS COULD REACH INTO THE LOW 90S WEST AND
NORTH CENTRAL...AND THE MID TO UPPER 80S ELSEWHERE.

MONDAY NIGHT INTO TUESDAY GETS TRICKY...AS MODELS DEVELOP ANOTHER
LOW PRESSURE SYSTEM OVER NEBRASKA/SOUTH DAKOTA ALONG THE PASSING
TROUGH. WITH THE HUDSON BAY LOW MOVING INTO QUEBEC...AND HIGH
PRESSURE EXPANDING OUT OF THE CANADIAN PRAIRIES...UPPER MICHIGAN IS
STUCK WITH A SOMEWHAT STATIONARY BOUNDARY THROUGH ROUGHLY TUESDAY
AFTERNOON. MODELS ARE CONSISTENT WITH DEVELOPING AN MCS OVER NORTH
DAKOTA/WESTERN MINNESOTA MONDAY NIGHT...THEN CARRYING IT INTO THE
CWA FOR TUESDAY...THOUGH THE EXACT PATH THE DECAYING MCS WILL TAKE
IS UNCERTAIN. THE GFS IS STRONGEST WITH THE HIGH PRESSURE SYSTEM
OVER THE CANADIAN PRAIRIES...SO IT SHIFTS THE DEVELOPING SURFACE LOW
IN SOUTH DAKOTA/NEBRASKA THROUGH WI AND SOUTHEASTWARD...WHEREAS THE
GEM/ECMWF/NAM ARE WEAKER WITH THE HIGH AND CARRY THE LOW FURTHER
NORTHWARD THROUGH UPPER MICHIGAN. EITHER WAY...TUESDAY LOOKS
FAVORABLE FOR LIKELY POPS.

AS FAR AS SEVERE POTENTIAL ON TUESDAY GOES...THE GFS HAS 2-3K J/KG
OF MUCAPE FOR MUCH OF THE CWA THROUGH EARLY AFTERNOON UNTIL THE
STATIONARY BOUNDARY IS FORCED OUT OF THE AREA BY THE APPROACHING
HIGH. 0-6KM SHEAR AT THIS TIME IS AROUND 30KTS EARLY WITH
WEST-NORTHWEST FLOW ALOFT. THE GFS HAS PWATS AROUND 200 PERCENT OF
NORMAL...WITH SOUNDINGS SATURATED THROUGH THE MID LEVELS. AS
MENTIONED IN PREVIOUS DISCUSSIONS...IF THE FRONTAL BOUNDARY IS
STRONG ENOUGH TO BREAK THROUGH THE CAP IN PLACE OVER MUCH OF THE
U.P. THEN THERE IS POTENTIAL FOR THEM TO BECOME SEVERE.

TEMPERATURES ON TUESDAY WILL COOL SLIGHTLY WITH MORE EXTENSIVE CLOUD
COVER AND 850MB TEMPS IN THE MID TEENS. HIGHS SHOULD RANGE FROM THE
70S TO THE LOW TO MID 80S...HOWEVER IF WE CAN GET MORE SUN THAN WHAT
IS CURRENTLY FORECAST...WOULD NOT BE SURPRISED TO SEE HIGHS APPROACH
90 AGAIN. GIVEN MODEL UNCERTAINTY...THIS IS NOT OUT OF THE QUESTION.

HIGH PRESSURE WILL MOVE INTO THE GREAT LAKES WEDNESDAY AFTERNOON
INTO THURSDAY...BRINGING QUIETER WEATHER TO UPPER MI. WITH 850MB
TEMPS RANGING FROM AROUND 10C TO 14C...EXPECT HIGHS IN THE 70S AND
LOW 80S. ANOTHER LOW PRESSURE SYSTEM WILL CROSS THE CANADIAN
PRAIRIES FRIDAY...AND THE GREAT LAKES ON SATURDAY....BRINGING THE
NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS INTO THE GREAT LAKES. HAVE
KEPT CONSENSUS POPS FOR NOW.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 130 PM EDT SAT JUL 19 2014

VFR CONDITIONS WILL PREVAIL THRU THE FCST PERIOD AT KIWD/KCMX/KSAW.
AN APPROACHING WEAKENING COLD FRONT AND DISTURBANCE MAY BRING A FEW
SHRA/TSRA INTO WRN UPPER MI THIS AFTN/TONIGHT. HOWEVER...CONFIDENCE
IS TOO LOW TO INCLUDE ANY MENTION OF SHRA DUE TO EXPECTED LIMITED
COVERAGE AND UNCERTAIN LOCATION OF SHRA DEVELOPMENT. IN
ADDITION...GUSTY SOUTH WINDS WILL CONTINUE AT ALL SITES TODAY...WITH
SOME GUSTS AS HIGH AS 20-25 KT.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 PM EDT SAT JUL 19 2014

SOUTHERLY WINDS WILL PREVAIL OVER MOST OF LAKE SUPERIOR THRU MON AS
HIGH PRES WILL BE LOCATED TO THE E WHILE A SERIES OF LOW PRES
SYSTEMS/TROFS MOVE ACROSS SRN CANADA. ONE LOW PRES SYSTEM WILL
FINALLY CROSS THE UPPER LAKES TUE BRINGING A WIND SHIFT TO THE N OR
NW. WINDS THRU THE FCST PERIOD WILL GENERALLY BE UNDER 20 KNOTS.
HOWEVER...THERE WILL BE OCNL PERIODS OF SLIGHTLY STRONGER WINDS
(15-25KT) AT THE HIGHER OBS PLATFORMS. THESE STRONGER WINDS WILL
AFFECT MAINLY THE E HALF OF LAKE SUPERIOR. SOME FOG MAY DEVELOP OVER
THE LAKE...ESPECIALLY AFTER SOME PCPN OCCURS. UNTIL THEN...FOG
DEVELOPMENT SHOULD BE CONFINED MOSTLY TO WRN AND NRN PORTIONS OF THE
THE LAKE WHERE FLOW IS MORE CONVERGENT.
&&

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

$$

SHORT TERM...MRD
LONG TERM...MCD
AVIATION...MRD
MARINE...MRD





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