Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 100356
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1156 PM EDT WED APR 9 2014

.SYNOPSIS...
ISSUED AT 318 PM EDT WED APR 9 2014

A NARROW RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE UPPER GREAT
LAKES THIS AFTERNOON WILL GIVE WAY TONIGHT AS A COLD FRONT
STRETCHING FROM CENTRAL CANADA AND ACROSS THE NORTHERN ROCKIES WILL
CROSS MICHIGAN THURSDAY.  THIS FRONT IS EXPECTED TO PUSH A BAND OF
RAIN ACROSS NORTHERN MICHIGAN THURSDAY...FOLLOWED BY A PERIOD OF DRY
WEATHER THURSDAY NIGHT AND THE FIRST PART OF FRIDAY BEFORE ANOTHER
FRONT BRING A SMALL CHANCE FOR SHOWERS TO THE REGION LATER FRIDAY
INTO FRIDAY NIGHT.

&&

.UPDATE...
ISSUED AT 1048 PM EDT WED APR 9 2014

JUST A QUICK UPDATE TO RAISE LOWER TEMPERATURES BY A COUPLE OF
DEGREES ACROSS NORTHERN LOWER. OTHERWISE...OVERNIGHT FORECAST ON
TRACK...THOUGH UPSTREAM SHOWERS ACROSS NORTHEAST MINNESOTA DUE IN
TOWARD DAYBREAK LOOKING A BIT PALTRY. THERE IS STILL SOME TIME TO
ORGANIZE OUT AHEAD OF THE APPROACHING COLD FRONT.

UPDATE ISSUED AT 733 PM EDT WED APR 9 2014

NOT A LOT GOING ON AT THE MOMENT WITH JUST A BAND OF MID LEVEL
CLOUDINESS PASSING ACROSS THE WESTERN FORECAST AREA. PRETTY QUIET
EVENING AND EARLY OVERNIGHT EXPECTED WITH MILD TEMPERATURES.
SHOWERS SHOULD THEN MOVE IN TOWARD DAYBREAK AS A WEAK COLD FRONT
APPROACHES FROM THE WEST.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 318 PM EDT WED APR 9 2014

...COLD FRONT AND ASSOCIATED SHOWERS ARRIVE TOWARDS DAYBREAK...

HIGH IMPACT WEATHER POTENTIAL: NONE.

PATTERN SUMMARY: EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS LONGWAVE
TROUGH AXIS ALONG THE EAST COAST OF NOAM PROGRESSING EAST...WITH
FIRMLY ENTRENCHED NORTHWEST FLOW ACROSS NORTHERN MICHIGAN GRADUALLY
BACKING AS THE MID AND UPPER LEVEL FEATURES STEADILY MOVE EAST.  A
LOOK UPSTREAM REVEALS OUR NEXT WEATHER-MAKER...A SHORTWAVE TROUGH
ALONG THE U.S./CANADIAN BORDER JUST EAST OF THE ROCKIES.  THIS
FEATURE WILL PULL A PLUME OF STEEP MID LEVEL LAPSE RATES FROM THE
ROCKIES EASTWARD...WITH THE GULF SLOWLY OPENING BACK UP AND
PROVIDING A BOOST IN MOISTURE AS THIS SYSTEM ARRIVES.  IN TERMS OF
SURFACE WEATHER FEATURES...THE SURFACE LOW ASSOCIATED WITH THIS
SHORTWAVE WILL PASS WELL NORTH OF MICHIGAN TONIGHT...WITH OUR FOCUS
CENTERED ON IT/S COLD FRONT THAT WILL BE ON OUR DOORSTEP BY THE END
OF THIS FORECAST PERIOD BY DAYBREAK THURSDAY.

PRIMARY FORECAST CONCERNS:  PRECIPITATION/THUNDER CONCERNS TONIGHT
AHEAD OF ARRIVING FRONT...AS WELL AS IT/S IMPACTS ON OVERNIGHT
TEMPERATURES.

THROUGH THIS EVENING: PATCH OF THICKER UPPER LEVEL CLOUDINESS OVER
NORTHERN LOWER WILL CONTINUE TO THIN AS IT PUSHES SOUTH AND EAST.
LOOKING UP STREAM...A BAND OF MID LEVEL MOISTURE EXISTS ON THE
LEADING EDGE OF THE ARRIVING MOISTURE PLUME AT H7.  THIS WILL PUSH
INTO THE CWA AS WE MOVE TOWARDS EVENING...WITH PARTLY TO
OCCASIONALLY MOSTLY CLOUDY SKIES EXPECTED. TEMPERATURES WILL ONLY
SLOWLY FALL AS WE MOVE THROUGH 00Z/8PM.

TONIGHT: COLD FRONT MARCHES FROM WESTERN LAKE SUPERIOR LATE THIS
EVENING...TO A POSITION ALONG THE NORTHWESTERN EDGE OF THE CWA
TOWARDS DAYBREAK.  LLJ RESPONSE IS VERY IMPRESSIVE AHEAD OF THIS
FEATURE...WITH 50KT SOUTHWESTERLY FLOW QUICKLY DEVELOPING DURING THE
EVENING AND CONNECTING TO A DEVELOPING MOISTURE PLUME OVER THE
SOUTHERN PLAINS AS THE GULF REOPENS.  THIS MOISTURE PLUME WILL
TRANSPORT 0.7-0.9" PWATS NORTH AND EAST TO A LOCATION JUST AHEAD OF
THE FRONT...COLLOCATED WITH GOOD LLEVEL CONVERGENCE AND MODEST MID
LEVEL QG SUPPORT. THIS SETUP SHOULD HAVE NO PROBLEM SUPPORTING A
BAND OF SHOWERS THAT SHOULD ARRIVE IN EASTERN UPPER AFTER 09Z.  HAVE
DELAYED POPS JUST A TAD BASED ON 12Z GUIDANCE AND ANTECEDENT DRY
LLEVEL AIRMASS...WITH NO PRECIP LIKELY SOUTH OF THE BRIDGE UNTIL
AFTER 11-12Z.

THUNDER:  FORECAST SOUNDINGS AHEAD OF THE FRONT DO SHOW STEEP MID
LEVEL LAPSE RATES /SOMEWHAT OF AN EML APPEARANCE/...BUT AS THE
INITIALLY DRY LLEVELS SATURATE... MUCAPES REMAIN BELOW 100 J/KG
/WITH QUICK LLEVEL COOLING REMOVING EVEN THIS INSTABILITY QUICKLY/
SO WHILE THERE WILL BE A CONVECTIVE APPEARANCE TO ECHOES...SEE NO
THUNDER THREAT AND WILL REMOVE MENTION.

QPF:  AMOUNTS THROUGH DAYBREAK OF AROUND ONE TENTH OF AN INCH LOOK
SOUND FOR WESTERN CHIP/MACK...WITH VALUES QUICKLY FALLING OFF TO THE
SOUTH AND EAST OF THIS.

WINDS:  WINDS WILL REMAIN COUPLED TONIGHT AS GRADIENT STRENGTHENS
WITH 1000 MB GEOSTROPHIC FLOW REACHING 40-50KTS AHEAD OF THE COLD
FRONT OVERNIGHT.  EXPECT SURFACE WINDS SOUTHWEST 10-15 MPH WITH
GUSTS TO 25 MPH.

TEMPERATURES /CONFIDENCE: MODERATE-HIGH/: TEMPERATURES REMAINING
MILD OVERNIGHT WITH WELL-MIXED BOUNDARY LAYER AND INCREASING CLOUDS.
DEWPOINTS WILL INITIALLY BE IN THE 20S...SO THERE IS ROOM TO COOL
DURING THE EVENING BEFORE THE GRADIENT STRENGTHENS...AND THERE WILL
ALSO BE ROOM TO COOL AS RAIN SATURATES THE LLEVELS OVER EASTERN
UPPER LATE.  THE SCENARIO ARGUES FOR TEMPS REMAINING AT OR ABOVE 40
FOR MOST SPOTS...AND WILL GO JUST A TAD BELOW THIS GIVEN THE
AFOREMENTIONED VARIABLES.

.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 318 PM EDT WED APR 9 2014

HIGH IMPACT WEATHER POTENTIAL: MINIMAL BUT LOW CONFIDENCE. SOME
RIVER FLOOD POTENTIAL LATE WEEKEND INTO EARLY NEXT WEEK WITH RAIN
AND REMAINING SNOW MELT.  ALSO LOW CONFIDENCE SNOWSTORM POTENTIAL
LATE SUNDAY NIGHT INTO MONDAY.

OVERVIEW: ACTIVE WEATHER PATTERN OVER THE NEXT SEVERAL DAYS WITH
SEVERAL PACIFIC WAVES MOVING ACROSS NORTHERN MICHIGAN IN GENERAL
PROGRESSIVE ZONAL FLOW.  LONGWAVE PATTERN UNDERGOES A TEMPORARY
RE-AMPLIFICATION EARLY NEXT WEEK WITH UPSTREAM RIDGING DRIVING
ANOTHER SHOT OF VERY COLD AIR /FOR MID APRIL/ INTO THE NORTHERN
LAKES.  THE FRONT EDGE OF THIS BRIEF PATTERN RE-ALIGNMENT MAY SEE A
LENGTHY WET PERIOD WITH POTENTIALLY SOME HEAVY RAIN.  THERE ALSO MAY
BE ENOUGH COLD AIR FOR BACKSIDE SNOW OVER PORTIONS OF THE AREA.

PRIMARY FORECAST CONCERNS/CHALLENGES: TEMPERATURE AND CLOUD TRENDS
THROUGHOUT THE FORECAST. RAIN CHANCES/COVERAGE THURSDAY AND OVER THE
WEEKEND INTO EARLY NEXT WEEK.  WILL ALSO LIKELY HAVE TO DEAL WITH
SOME PRECIPITATION TYPE ISSUES BY LATER SUNDAY NIGHT INTO MONDAY.

COLD FRONT MOVES ACROSS THE AREA ON THURSDAY.  NARROW BAND OF 0.80
PWAT VALUES COMBINED WITH ENHANCED UPWARD MOTION IN RFQ OF 300MB JET
AND LOW LEVEL CONVERGENCE SHOULD RESULT IN A SWATH OF SHOWERS ALONG
THE FRONT.  PRECIPITATION WILL ENTER NORTHWEST PORTIONS OF THE AREA
SHORTLY BEFORE SUNRISE AND PROCEED ACROSS THE AREA THROUGHOUT THE
DAY.  NOT VERY IMPRESSIVE THUNDER CHANCES GIVEN ANEMIC INSTABILITY
AND FROPA IN THE FIRST HALF OF THE DAY.  BECAUSE OF THIS...WILL
REMOVE THUNDER FROM THE FORECAST.  IMPRESSIVE PUSH OF DRY AIR BEHIND
THE FRONT LATE THURSDAY AFTERNOON INTO EARLY FRIDAY LEADING TO DRY
WEATHER AND CLEARING SKIES.  VERY DIFFICULT TEMPERATURE FORECAST ON
THURSDAY GIVEN CLOUDS/RAIN BUT RELATIVELY WARM TEMPS ALOFT...WILL
GENERALLY CARRY READINGS IN UPPER 40S TO MID 50S /WARMEST
SOUTHEAST/.

PROGRESSIVE NATURE OF THE PATTERN BEGINS TO TAKE ITS TOLL ON
FORECAST CONFIDENCE BY THE SECOND HALF OF FRIDAY INTO EARLY NEXT
WEEK.  12Z MODELS SHOW ANOTHER WEAK PACIFIC WAVE INTO THE AREA BY
LATER FRIDAY AFTERNOON/EVENING...UNIMPRESSIVE MOISTURE PROFILES WITH
THIS FEATURE SHOULD RESULT IN VERY LIGHT RAIN AMOUNTS /MAINLY
EASTERN UPPER/. AS PREVIOUS SHIFT MENTIONED...SOME HINT IN THE
MODELING OF LOW LEVEL CONVERGENCE OVER EASTERN UPPER WHICH COULD
ENHANCE RAINFALL...BUT OVERALL THIS LOOKS LIKE A RELATIVELY MINOR
EVENT.  GROWING MODEL DIVERGENCE INTO EARLY NEXT WEEK WITH EXACT
PLACEMENT OF FEATURES WHICH WILL HAVE A LARGE IMPACT ON THE DAY TO
DAY FORECAST DETAILS.  UPSTREAM LONGWAVE PATTERN AMPLIFIES OVER THE
WEEKEND WITH AT LEAST SOME POSSIBILITY OF NORTHERN/SOUTHERN STREAM
PHASING LEADING TO A MORE SIGNIFICANT STORM ON MONDAY.  A WIDESPREAD
RAIN EVENT SHOULD DEVELOP ACROSS THE AREA SATURDAY NIGHT/SUNDAY.
UNCERTAINTY IN WHETHER WE WILL SEE A BREAK IN THE RAIN FOR A TIME ON
SUNDAY BEFORE NEXT WAVE MOVES UP ALONG THE FRONTAL BOUNDARY FROM THE
SOUTH SUNDAY NIGHT/MONDAY.  AS MENTIONED IN THE IMPACT SECTION AT
THE TOP...THIS WOULD BE THE TIMEFRAME TO LOOK MORE CLOSELY AT RIVER
FLOODING POTENTIAL WITH SLOW MOVING FRONTAL BOUNDARY...EXCELLENT
GULF TAP AND PWATS OF 1.5 INCHES SUPPORTING HEAVY RAIN POTENTIAL. AS
COLDER AIR WORKS INTO THE AREA ON THE BACKSIDE OF SURFACE LOW LATE
SUNDAY/MONDAY...RAIN WILL LIKELY CHANGE TO OVER TO SNOW /AT LEAST
OVER WEST-NORTHWEST PORTIONS OF THE AREA/.  STILL LOTS OF QUESTION
MARKS ABOUT HOW THIS WILL ALL PLAY OUT BUT CERTAINLY SOMETHING THAT
BEARS WATCHING.  SEASONABLY MILD TEMPERATURES /40S-50S/ SATURDAY
TRANSITIONING TO HIGHS WELL BELOW NORMAL IN THE 30S TO MID 40S BY
EARLY NEXT WEEK.  MAY EVEN CHALLENGE A FEW RECORD LOWS NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1152 PM EDT WED APR 9 2014

CONTINUED VFR CONDITIONS THROUGH THE EARLY MORNING HOURS. A 2 TO
4 HOUR DURATION BAND OF RAIN SHOWERS AND ASSOCIATED MVFR
CONDITIONS ARE THEN EXPECTED TOWARD DAYBREAK INTO MID MORNING WITH
THE PASSAGE OF A WEAK COLD FRONT. WINDS...SOUTH/SOUTHWEST WINDS
SHIFTING INTO THE WEST LATER THIS MORNING AND BECOMING GUSTY
THROUGH THE AFTERNOON. HIGH PRESSURE WILL THEN BUILD IN THURSDAY
NIGHT DIMINISHING THE WINDS IN THE EVENING. CONTINUED LLWS
THROUGH THE EARLY MORNING HOURS.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...AS
SYNOPSIS...JPB
SHORT TERM...ARNOTT
LONG TERM...JK
AVIATION...AS






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