Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 152037
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
437 PM EDT WED APR 15 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 332 PM EDT WED APR 15 2015

VERY DRY AND QUIET WEATHER CONTINUES UNDER SFC AND UPPER RIDGING.
THE DRY AIRMASS OVERHEAD HAS MIXED TO DEW POINTS IN THE LOW TO MID
TEENS OVER THE INTERIOR W HALF...AND WITH TEMPS IN THE 60S SFC RH
VALUES HAVE FALLEN INTO THE LOW TO MID TEENS AS WELL.

OVER THE DOWNSLOPING AREAS /FROM A SSE WIND/ TONIGHT...RH RECOVERY
WILL BE POOR WITH MAX RH VALUES TONIGHT IN THE MID 40 PERCENT RANGE
OVER THESE AREAS. INLAND...MAX RH VALUES WILL ONLY BE 60-85 PERCENT.

THURSDAY WILL SEE A CHANGE ON PATTERN BUT NOT MUCH OF A CHANGE IS
OBSERVED CONDITIONS. AN UPPER WAVE MOVING INTO THE AREA WILL LEAD TO
A SHALLOW LAYER OF MOISTURE ABOVE 800MB...BUT THE AIRMASS BELOW WILL
CONTINUE TO BE VERY DRY. THINK THAT COMBINATION OF WEAK FORCING WITH
THE WAVE AND DRY LOW LEVEL AIR WILL KEEP THE AREA DRY. SHOULD SEE
HIGHS IN THE 60S AWAY FROM LAKE MICHIGAN WITH MIN RH VALUES AROUND
20 PERCENT INTERIOR W HALF AND IN THE 30S INTERIOR E.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT WED APR 15 2015

AFTER A QUIET AND GENERALLY WARM REST OF THIS WEEK...SIGNIFICANT
AMPLIFICATION OF THE FLOW IS EXPECTED THIS WEEKEND AND EARLY NEXT
WEEK AS A SHARP RIDGE BUILDS THRU WRN CANADA. THIS WILL FORCE A DEEP
TROF TO DEVELOP DOWNSTREAM WITH AXIS ROUGHLY OVER THE MISSISSIPPI
VALLEY BY MON. TYPICAL FOR THIS TIME OF YEAR...CLOSED LOWS
FREQUENTLY DEVELOP...AND THIS TROF WILL QUICKLY EVOLVE IN THAT
DIRECTION AS MAJORITY OF GUIDANCE INCLUDING GFS/GEM ENSEMBLES SHOW
EVOLUTION INTO A LARGE/COLD MID-LEVEL LOW OVER THE VICINITY OF THE
UPPER GREAT LAKES. MAY BE DIFFICULT TO DISLODGE THE LOW NEXT WEEK
ONCE IT DEVELOPS. SO...AFTER A WARM/DRY REST OF THIS WEEK...NEXT
WEEK WILL BE COLD AND GENERALLY UNSETTLED WITH PERIODIC CHANCES OF
SNOW AND RAIN SHOWERS. FROM A PCPN PERSPECTIVE...THE BIGGEST
CHALLENGE IS HOW THE SHARP PATTERN AMPLIFICATION INTERACTS WITH WHAT
IS CURRENTLY AN IMPRESSIVE LOOKING TROF CLOSING OFF OVER UT/CO.
MEDIUM RANGE GUIDANCE TODAY IS IN MUCH BETTER AGREEMENT IN SHOWING
THE AMPLIFICATION OF THE FLOW PICKING UP THE MID-LEVEL LOW AND
FORCING THE OPENED UP SYSTEM/REMNANT ENERGY NE INTO THE GREAT LAKES
REGION. RANGE OF POSSIBILITIES STILL INCLUDE A SIGNIFICANT RAIN
EVENT TO A RAIN CHANGING TO ACCUMULATING SNOW EVENT TO MINIMAL PCPN
IF THE SRN ENERGY DOES NOT LIFT FAR ENOUGH N AND W WITHIN THE
AMPLIFYING PATTERN. OPERATIONAL MEDIUM RANGE MODELS WEAKEN THE
ENERGY DRAMATICALLY AS IT LIFTS NE (WILL BE INTERESTING TO SEE IF
THAT ACTUALLY HAPPENS)...SO THE LOWEST PROBABILITY OUTCOME RIGHT NOW
IS ONE THAT BRINGS A SIGNIFICANT PCPN PRODUCING SYSTEM WITH A
PROMINENT DEFORMATION PCPN SHIELD INTO THE UPPER LAKES EARLY NEXT
WEEK. THAT SAID...THERE HAVE BEEN AND THERE STILL ARE SOME GFS/GEM
ENSEMBLES THAT DO SHOW SUCH A SCENARIO...SO IT CAN`T BE RULED OUT.

BEGINNING THU NIGHT...TAIL END OF SHORTWAVE TRACKING FROM HUDSON BAY
INTO QUEBEC WILL PASS ACROSS THE AREA THU NIGHT. FORCING FROM THE
RIGHT ENTRANCE OF AN UPPER JET STREAK AND MAIN DEEP LAYER QVECTOR
CONVERGENCE...WEAK AT THAT...PASS N OF THE AREA...SUPPORTING BEST
CHC OF -SHRA N OF HERE. ACROSS UPPER MI...VERY WEAK FORCING/WEAK
FRONTAL BOUNDARY AND WEAK MOISTURE TRANSPORT ALL SUGGEST PROSPECT OF
ANY PCPN IS VERY LIMITED AS SHORTWAVE PASSES. THUS...WILL RETAIN DRY
FCST FOR THU NIGHT.

IN THE MAIN FLOW TO THE N...ANOTHER SHORTWAVE IS FCST TO TRACK FROM
THE CANADIAN ROCKIES THU AFTN TO NRN ONTARIO FRI. MODELS HAVE
TRENDED TO MUCH BETTER AGREEMENT ON THIS WAVE WITH GEM/GFS/NAM
MOVING TO THE ECMWF SCENARIO WHICH HAS BEEN FARTHER N THAN THOSE
MODELS FOR SEVERAL RUNS. WITH THE TRACK OF THE SHORTWAVE JUST N OF
LAKE SUPERIOR...BEST FORCING AND POTENTIAL FOR PCPN WILL PASS BY TO
THE N. REMOVED SCHC POPS FROM INHERITED FCST IN FAVOR OF DRY
WEATHER. EXPECT HIGH TEMPS FRI IN THE 60S AWAY FROM LAKE MODERATION.
A FEW SPOTS MAY REACH 70F. INTERIOR RH SHOULD FALL TO 25-30PCT...
AND WINDS MAY BE A LITTLE GUSTY TO 15-20MPH AT TIMES...KEEPING FIRE
WX A CONCERN.

IN THE WAKE OF THE SHORTWAVE...HIGH PRES BUILDS INTO THE AREA FOR
SAT. WITH THE HIGH ENDING UP OVER LAKE SUPERIOR IN THE AFTN...IT
WILL BE A MUCH COOLER DAY NEAR LAKE SUPERIOR...ESPECIALLY FROM THE
KEWEENAW EASTWARD. RIGHT ALONG THE SHORE...TEMPS SHOULDN`T GET OUT
OF THE 30S. IN THE INTERIOR W HALF...TEMPS SHOULD RISE TO AROUND 60F
UNDER SUNNY SKIES.

SUN/MON...WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH OF CURRENT
AND RECENT MEDIUM RANGE GUIDANCE FOR THE EVOLUTION OF THE SRN
ROCKIES ENERGY INTO THE GREAT LAKES AHEAD OF THE TROF AMPLIFICATION
OCCURRING INTO THE PLAINS/MISSISSIPPI VALLEY. IT APPEARS THERE MAY
END UP BEING TWO SURGES OF PCPN OR SFC LOW PRES WAVES...ONE
ASSOCIATED WITH LEAD ENERGY SWINGING UP FROM MEXICO AND A SECOND
ASSOCIATED WITH THE MAIN REMNANT OF THE ROCKIES MID LEVEL LOW.
LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN SPREADING INTO UPPER MI SUN
AND THEN CONTINUE INTO MON. AIR MASS SHOULD COOL ENOUGH TO ALLOW
SOME SNOW TO BEGIN MIXING WITH THE RAIN OVER THE W ON MON. PTYPE
WILL THEN BECOME ALL SNOW ACROSS THE FCST AREA MON NIGHT FOR
WHATEVER PCPN LINGERS.

TUE/WED...LARGE/COLD MID-LEVEL LOW WILL HAVE DEVELOPED AND WILL BE
CENTERED IN THE VCNTY OF THE UPPER GREAT LAKES. COLD AIR
ALOFT/SPRING DAYTIME HEATING AND POTENTIAL OF SHORTWAVES ROTATING
THRU THE AREA WITHIN THE LARGE MID-LEVEL LOW CIRCULATION SUGGEST AT
LEAST SCT SHOWERY PCPN (MOSTLY SNOW BUT SOME RAIN AS WELL DURING
PEAK HEATING) BOTH DAYS WITH BEST COVERAGE IN THE AFTN INLAND FROM
LAKE SUPERIOR WHERE HEATING IS BEST. HIGH TEMPS BOTH DAYS SHOULD BE
IN THE MID 30S TO MID 40S...WARMEST SCNTRL.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 132 PM EDT WED APR 15 2015

VFR CONDITIONS WILL CONTINUE FOR THIS FORECAST PERIOD.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT WED APR 15 2015

WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS THROUGH SUNDAY AS
EVEN WITH A COUPLE FRONTS WORKING THROUGH THE AREA. THE OVERALL
PRESSURE GRADIENT STAYS WEAK.
&&

.HYDROLOGY...
ISSUED AT 332 PM EDT WED APR 15 2015

SEEMS THAT WITHOUT ANY SIGNIFICANT ADDITIONAL PRECIPITATION ADDED TO
THE ONGOING SNOWMELT...AT LEAST FOR THE REST OF THIS WEEK...MAINLY
LOOKING AT A FEW BANKFULL ISSUES ON SOME RIVERS WITH CONTINUATION OF
LOW-END ADVISORIES. BELOW NORMAL TEMPERATURES ARE EXPECTED MONDAY
THROUGH MUCH OF NEXT WEEK...WHICH WILL LIMIT MELTING OF ANY
REMAINING SNOW PACK AND REDUCE RIVER LEVELS.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...ROLFSON
AVIATION...TITUS
MARINE...TITUS
HYDROLOGY...TITUS



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