Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 190745
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
345 AM EDT TUE AUG 19 2014

.SYNOPSIS...
ISSUED AT 342 AM EDT TUE AUG 19 2014

PERIODS OF SHOWERS AND A FEW THUNDERSTORMS WILL BE FOUND OVER
NORTHERN MICHIGAN TODAY INTO WEDNESDAY...AS UPPER LEVEL LOW PRESSURE
SPINS OVERHEAD. RAINFALL WILL BE LOCALLY HEAVY...WITH SOME SPOTS
PERHAPS PICKING UP IN EXCESS OF 2 INCHES BY WEDNESDAY AFTERNOON.
THAT SYSTEM WILL DEPART WEDNESDAY NIGHT...JUST IN TIME FOR A WARM
FRONT TO SLOWLY INCH NORTH THROUGH THE GREAT LAKES FOR LATE WEEK.
THAT FEATURE WILL DELIVER ADDITIONAL CHANCES FOR SHOWERS AND
THUNDERSTORMS RIGHT ON THROUGH THE WEEKEND.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 342 AM EDT TUE AUG 19 2014

...LOCALIZED HEAVY RAINS EXPECTED TODAY/TONIGHT...

HIGH IMPACT WEATHER POTENTIAL: LOCALLY HEAVY RAINFALL AMOUNTS IN
EXCESS OF 2 INCHES POSSIBLE TODAY INTO TONIGHT. SOME NON-SEVERE
CONVECTION ALSO EXPECTED.

PATTERN SUMMARY: SHARP UPPER TROUGH AXIS IS MEANDERING EASTWARD
THROUGH MINNESOTA EARLY THIS MORNING...WITH AN ACCOMPANYING WEAK
SURFACE LOW ANALYZED NEAR THE TWIN CITIES AS OF 06Z. A WAVERING
STATIONARY/WARM FRONT IS ATTACHED TO THIS FEATURE BUT HAS RESISTED
MUCH EASTWARD PROGRESS MUCH OF YESTERDAY AND OVERNIGHT...COURTESY OF
THE STILL QUITE COLD WATERS OF LAKE MICHIGAN. THAT WILL CHANGE
TOWARD SUNRISE AND INTO TUESDAY AS THE UPPER LOW PINWHEELS OVERHEAD
BY LATE IN THE DAY...WITH SAID SURFACE LOW FLOATING ACROSS NORTHERN
LAKE MICHIGAN INTO THE EVENING HOURS...LIFTING THE SURFACE BOUNDARY
NORTH SOMEWHERE INTO NORTHERN LOWER...BUT AGAIN MEETING RESISTANCE
FROM THE COLD GREAT LAKE WATERS UP TOWARD THE TIP OF THE MITT.

FORECAST DETAILS: ON A SOMEWHAT BASIC LEVEL...THIS IS A RELATIVELY
STRAIGHTFORWARD FORECAST FROM A PRECIP STANDPOINT. IT SHOULD RAIN
JUST ABOUT EVERYWHERE AT SOME POINT THROUGHOUT THE DAY...COURTESY OF
NOTABLE MID LEVEL DIFFLUENCE OVERTAKING NORTHERN MICHIGAN JUST AHEAD
OF THE UPPER LOW MOVING INTO WISCONSIN. COMBINE THAT WITH AN
IMPRESSIVE INFLUX OF MOISTURE (PWATS CRUISING TO BETWEEN 1.5 AND
1.75 INCHES PER UPSTREAM OBS) AND WEAK BUT PERSISTENT LOW/MID LEVEL
WARM ADVECTION ASCENT...AND PERIODS OF SHOWERS SHOULD BE THE
RESULT...THOUGH THE EXACT PLACEMENT AND TIMING OF EACH BATCH IS
TRICKY AT BEST. AT THIS POINT...THE BETTER CHANCES FOR WIDESPREAD
COVERAGE LOOK TO COME DURING THE AFTERNOON...WHEN A MORE DIURNAL
COMPONENT WILL COME INTO PLAY...COMPLETE WITH CLASSIC SEMI-TROPICAL
SKINNY CAPE PROFILES UP AROUND 600-900 J/KG...PERHAPS GREATER SOUTH
OF M-32 WHERE WE MAY MUSTER SOME BETTER HEATING SOUTH OF THE "WARM"
FRONT.

AS HAS BEEN DISCUSSED AT LENGTH...THE BIGGEST CONCERN IS LOCALIZED
HEAVY RAINS GIVEN SUCH HIGH PWATS...HIGH FREEZING LEVELS UP AROUND
12-13KFT...AND LIMITED STEERING FLOW OF ONLY 10 TO MAYBE 20 KNOTS
THROUGH THE AFTERNOON. BASED ON HISTORY WITH THIS SYSTEM OVER THE
PAST SEVERAL DAYS...ABOVE-MENTIONED SKINNY CAPE PROFILES SHOULD HAVE
LITTLE TROUBLE YIELDING CONVECTIVE ELEMENTS (WITH A LIGHTNING
THREAT) WITHIN AN OVERALL BROADER AXIS OF SHOWERS. BASED ON UPSTREAM
OBS OVER THE PAST 5 DAYS...WOULD NOT AT ALL BE SHOCKED TO SEE SOME
SPOTS PICK UP IN EXCESS OF 2 INCHES OF RAIN TODAY INTO THIS
EVENING...AND WILL OF COURSE CONTINUE TO HIGHLIGHT THIS THREAT IN
THE HWO AND ON SOCIAL MEDIA. WITH THAT SAID...THE OVERALL FLOODING
THREAT SHOULD BE MARGINAL...AND WOULD ONLY BECOME AN ISSUE IF
GREATER THAN 3 INCHES CAN BE REALIZED OVER SHORT PERIODS OF TIME PER
CURRENT FLASH FLOOD GUIDANCE...OR IF SOME OF THE HEAVIER RAINS FALL
INTO NORTHEAST LOWER WHERE SOILS REMAIN WET FROM LAST WEEK`S HEAVY
RAIN EVENT. SOMETHING TO WATCH FOR SURE...BUT OF COURSE THIS IS MORE
OF A NOWCAST TYPE OF SETUP. SEVERE WEATHER POTENTIAL SHOULD BE QUITE
LIMITED BY A LACK OF INSTABILITY AND WEAK DEEP LAYER SHEAR...THOUGH
AS WAS SEEN ACROSS WISCONSIN YESTERDAY...BETTER THAN EXPECTED
HEATING COULD RESULT IN SOME BEEFIER STORMS...PARTICULARLY WITH THE
POSSIBILITY OF PRECIP-LOADING IN SUCH A MOIST ENVIRONMENT AND AT
LEAST SOME SEMBLANCE OF LOCALIZED HIGHER SHEAR IN THE VICINITY OF
THE NEARBY BOUNDARY.

LOOKING INTO TONIGHT...THE UPPER LOW WILL WORK PRETTY MUCH
OVERHEAD...REFOCUSING THE AXIS OF BETTER MID LEVEL DIFFLUENCE/SUPPORT
OUT OVER LAKE HURON BUT PERHAPS WRAPPING BACK NORTH INTO EASTERN
UPPER. WILL MAINTAIN THE HIGHEST POPS IN THE SORT OF CONFIGURATION...
WHILE ALSO ACCOUNTING FOR THE ARRIVING REMNANTS OF WHAT WILL SURELY
BE ADDITIONAL CONVECTION POPPING BENEATH THE UPPER LOW OVER
WISCONSIN.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 342 AM EDT TUE AUG 19 2014

...TURNING MORE SUMMER-LIKE?...

IMPACTS: LIGHTNING...WITH SEVERAL CHANCES FOR SHOWERS AND STORMS.

SYNOPTIC PATTERN/EVOLUTION:

CLOSED UPPER/SFC LOWS TRAVERSE THE GREAT LAKES WEDNESDAY AND
WEDNESDAY NIGHT. AFTERWARD...A SLOW TRANSITION TO SOMETHING WE HAVE
BEEN TRYING FOR ALL SUMMER...SOME ACTUAL POSSIBLE RIDGING...WARMTH
AND HUMIDITY WITH BOTH NOCTURNAL AND DIURNAL CHANCES FOR SHOWERS AND
STORMS. THERE IS SOME UNCERTAINTY OF COURSE IN THE LATER PARTS OF
THE FORECAST...WITH HINTS THAT SUMMER CONDITIONS HOLD INTO EARLY
NEXT WORK WEEK. THAT SAID...THERE ARE ALSO HINTS THAT WE TRY AND
REBUILD THE MORE COMMON TROUGHING OVER THE GREAT LAKES.

MAIN FORECAST CONCERNS: POTENTIAL LOCALLY HEAVY RAIN WEDNESDAY AND
ALSO TRYING TO MAP OUT THE CHANCES FOR SHOWERS AND STORMS THE
FOLLOWING SEVERAL DAYS.

WEDNESDAY AND WEDNESDAY NIGHT:

UPPER/SFC LOWS OVERHEAD ON WEDNESDAY WITH DEPARTING DEEP LAYER
FORCING BY AFTERNOON/EVENING. VORTICITY MAXIMA WILL BE ROTATING
AROUND THE UPPER LOW...THE POSITION OF THEM HAVING AT LEAST SOME
DEGREE OF UNCERTAINTY. RIGHT NOW...WITH BEST -DIVQ CROSSING NE LOWER
AND EASTERN SECTIONS OF CHIP/MACK COUNTIES IN UPPER MICHIGAN. BEST
CHANCES RESIDE THERE IN THE MORNING. DEEP MOISTURE IS AVAILABLE WITH
LOW LEVEL CLOUDINESS LIKELY BREAKING UP SOME IN THE AFTERNOON FOR
SOME BL HEATING. WITH WEAK FLOW...TEMPS IN THE LOW TO MID 70S...AND
DEW POINTS IN THE LOW TO MID 60S...AM LOOKING FOR AN UPTICK IN
CONVECTION AND STORMS. THESE LIKELY MORE SO IN THE INTERIOR SECTIONS
DUE TO LAKE BREEZE CONVERGENCE...AND ALSO MORE SO IN NRN LOWER ALONG
AND EAST OF I-75. AMOUNTS OF HEATING DEPENDENT ON COVERAGE/INTENSITY
OF STORMS...BUT SCATTERED ACTIVITY SEEMS MORE THAN REASONABLE. THERE
IS NO EXPECTATION FOR SEVERE WEATHER WITHOUT GOOD WIND...BUT WE DO
HAVE THE ABILITY TO WORK WITH UPWARDS OF 1000J/KG. THIS NOT ENOUGH
WITH HIGH FREEZING LEVELS FOR TOO MUCH IN THE WAY OF HAIL.
HOWEVER...DO SEE THE ABILITY TO RECEIVE SOME LOCALLY HEAVY RAINFALL
WITH PWATS AROUND 1.5`-1.75"...AND VIRTUALLY NO WIND FOR SLOW STORM
MOVEMENT. COULD SEE SOME OF THIS ACTION HANGING ONTO MAINLY NE
LOWER IN THE EVENING UNTIL LOSS OF HEATING AND UPPER/SFC LOWS
DEPART.

THURSDAY AND THURSDAY EVENING:

NOT REALLY IN A FAVORABLE PATTERN FOR CONVECTION WITH RISING MID
LEVEL HEIGHTS...A DRYING ATMOSPHERE...AND AT LEAST SOME EXPECTATION
OF SUBSIDENCE. HOWEVER...WEAK WINDS WILL RESULT IN WEAK BL
ADVECTIONS...AND MORE SUNSHINE...WITH REMNANT DECENT DEW POINTS IN
THE LOWER TO MIDDLE 60S. THE RESULT IN WARMER EXPECTED TEMPERATURES
AND RESULTANT POTENTIAL INSTABILITY FOR DIURNALLY DRIVEN CONVECTION.
DEFINITELY UNCERTAINTY HERE...WITH SOME DATA SUGGESTING GREATER
DRYING AND SUBSIDENCE...BUT THE CHANCE IS THERE. WILL KEEP THE
CURRENT CHANCES FOR DIURNALLY DRIVEN SHOWERS AND STORMS...WITHIN
EXPECTED LAKE BREEZE CONVERGENCE AREAS OF INTERIOR SECTIONS OF BOTH
EASTERN UPPER AND NRN LOWER...BUT OBVIOUSLY HAVE IT FOR THE
AFTERNOON AND EVENING HOURS. STEERING FLOW OUT OF THE NW WOULD
LIKELY RESULT IN NE LOWER AGAIN GETTING A BETTER SHOT AT CONVECTION.

THURSDAY NIGHT ONWARD:

PLENTY OF UNCERTAINTY HERE TOO. THIS IS THE TRANSITION PERIOD TO
RISING MID LEVEL HEIGHTS...DUE TO TROUGHING ACROSS THE WESTERN
CONUS...AND THE EFFORT TO BUILD IN MORE HEAT. INITIAL SHORTWAVE
ENERGY EXPECTED TO EJECT INTO THE CENTRAL PLAINS...WITH LOW PRESSURE
AND A WARM FRONT LIFTING CLOSER TO THE WESTERN GREAT LAKES. THE NRN
EXTENT OF WHICH IS IN SOME QUESTION WITH SUCH FLAT INITIAL RIDGING.
MODELS ARE LIKELY KEYING IN ON A BIT STRONGER SHORTWAVE CROSSING
MANITOBA INTO ONTARIO THURSDAY NIGHT...TO HELP DRAG THE WARM FRONT
TOWARD US. THIS PUTS US ON THE NRN FRINGE OF A RING OF FIRE. MOST OF
THE TIME THIS RESULTS IN ANY CONVECTION DROPPING SW OF US...BUT WE
ARE AT LEAST IN A SMALL CHANCE FOR SEEING SOMETHING ACROSS NW LOWER.

FLOW REMAINS PRETTY WEAK ALOFT...AND THERE REALLY ISN`T TOO MUCH
DESIRE TO BRING THIS FRONT FURTHER NORTH FRIDAY AND FRIDAY
NIGHT...BUT WEAK VORTICITY BLEEDING IN OVER US...AND AXIS OF DEEPER
MOISTURE/PWATS OVERHEAD...GONNA HAVE AT LEAST CHANCE FOR MORE
SHOWERS AND STORMS. THIS CHANCE IS BETTER THAN THURSDAY NIGHT...AS
THE LOW LEVEL FORCING (LLJ) AND SLIGHTLY BETTER LAPSE RATES CREEP
EVER CLOSER.

THE WEEKEND...MOST UNCERTAINTY. THE MAIN TROUGHING FROM THE WESTERN
CONUS WILL BE KEY. DATA SUGGESTING EITHER HOLDING ACROSS MORE OF THE
NRN ROCKIES...OR LIFTING THROUGH MANITOBA/ONTARIO. THAT IS QUITE THE
SIGNIFICANT DIFFERENCE. THE LATTER IDEA WOULD RESULT IN INCREASING
FLOW ALOFT AND DRIVING THE WARM FRONT AND SFC LOW THROUGH US WITH
GREATER CHANCES FOR SHOWERS/STORMS. THE LATTER RESULTS IN INCREASING
MID LEVEL HEIGHTS AND KEEPING THE MAIN ACTION WELL WEST OF US. GONNA
TEND TO RIDE THE IDEA OF RIPPING THE FRONTS THROUGH HERE SINCE WE
HAVE HAD A HARD TIME DEVELOPING ANY SORT OF SIGNIFICANT RIDGING THIS
SUMMER. EITHER WAY...WE LOOK TO HAVE WARMER MORE SUMMER LIKE WEATHER
THROUGH AT LEAST SUNDAY.

EARLY NEXT WORK WEEK...DUE TO THE UNCERTAINTY ABOVE...THIS IS TOUGH
TO FIGURE....BUT AM GOING WITH NO PRECIP AND COOLER. IF YA WANT
SUMMER TO CONTINUE INTO THIS PERIOD...BE ROOTING FOR THE ECMWF IN
THESE LATER PERIODS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1158 PM EDT MON AUG 18 2014

PERIODS OF MVFR TO PERHAPS IFR RESTRICTIONS THRU TUESDAY DUE TO
SHRA/TSRA.

LOW PRESSURE OVER WESTERN WI WILL MOVE SLOWLY EAST TOWARD
NORTHERN LAKE MI BY TUESDAY AFTERNOON. MOISTURE WILL MOVE
NORTHWARD AHEAD OF THE LOW...RESULTING IN INCREASING SHRA/TSRA
COVERAGE ACROSS NORTHERN MI OVERNIGHT AND TUESDAY. DIFFICULT TO
PRECISELY TIME THE BEST THREAT FOR PRECIP AT THIS TIME...AND IN
PARTICULAR ANY TSRA. PERIODS OF MVFR CIGS/VSBYS ARE LIKELY AT
TIMES. THERE ARE CHANCES FOR BRIEF IFR CONDITIONS...WITH THE
HIGHEST LIKELIHOOD AT APN TUESDAY EVENING.

LIGHT WINDS TONIGHT...S TO SE BREEZE TUESDAY.


&&

.MARINE...
ISSUED AT 342 AM EDT TUE AUG 19 2014

WEAK LOW PRESSURE OVER WISCONSIN THIS MORNING WILL INTENSIFY
SLIGHTLY AS IT WORKS INTO NORTHERN LAKE MICHIGAN TONIGHT AND THEN
MEANDERS OVERHEAD THROUGH WEDNESDAY. AHEAD OF THIS SYSTEM...WINDS
WILL PICK UP FROM THE SOUTH TO SOUTHEAST BUT GENERALLY REMAIN BELOW
SMALL CRAFT ADVISORY LEVELS. THE EXCEPTION WILL BE UP THE LAKE HURON
COAST OF NORTHERN LOWER AND INTO WHITEFISH BAY WHERE SOUTHEASTERLY
FLOW WILL BE ENHANCED...WITH PERIODIC GUSTS TO AROUND 25 KNOTS AND
HIGHER WAVES EXPECTED. WINDS WILL QUICKLY SUBSIDE TONIGHT INTO
WEDNESDAY AS THE GRADIENT RELAXES...WITH SIMILAR CONDITIONS OF LIGHT
WINDS AND LOW WAVES EXPECTED TO ROUND OUT THE WORK WEEK.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 11 PM EDT THIS
     EVENING FOR LHZ346>349.
LM...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.

&&

$$

SYNOPSIS...LAWRENCE
SHORT TERM...LAWRENCE
LONG TERM...SMD
AVIATION...JZ
MARINE...LAWRENCE






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