Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 271055
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
655 AM EDT FRI MAR 27 2015

.SYNOPSIS...
ISSUED AT 447 AM EDT FRI MAR 27 2015

IT WILL BE A COLD LATE MARCH DAY TODAY...BUT WITH LITTLE MORE
THAN FLURRIES EXPECTED. HIGHS WILL ONLY RECOVER INTO THE UPPER
20S TO LOWER 30S TODAY. SKIES WILL BECOME CLEAR TO PARTLY CLOUDY
OVERNIGHT AND THE WINDS WILL DIMINISH. THIS WILL ALLOW THE
TEMPERATURE TO PLUMMET INTO THE TEENS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EDT FRI MAR 27 2015

CORE OF ARCTIC SFC RIDGE ACRS UPR MIDWEST TO SETTLE INTO WESTERN
GRTLKS BY 12 UTC SAT. CONTD DRYING WITH PWAT FALLING TO AROUND
0.10 /ONLY 0.05 INCHES ABOVE RECORD REGIONAL MINS/ LATER TODAY.
DRY/SUBSIDENT AMBIENT ENVIRONMENT WITH LOW BASED CAPPING
SUBSIDENT INVERSION HEIGHTS TO BE PRIMARY NEGATIVE FACTORS
AGAINST APPRECIABLE LES RESPONSE. DESPITE SRN LK MI LK/8H THERMAL
DIFFERENTIALS PEAKING INTO THE UPR TEENS WITH LK INDUCED CAPES TO
NEAR 300 J/KG MIDDAY AND LKS HURON/ERN LK SUPR DIFFERENTIALS TO
LWR 20S ALONG WITH CYCLONIC 925-8H FLOW THROUGH WRN
GRTLKS...STILL ONLY EXPECT MODICUM OF LES RESPONSE OUTSIDE OF
MORE FOCUSED WRN LK MI SHORELINE CONVERGENCE BAND THAT WILL
REMAIN WEST OF CWA. WILL COVER WITH VARYING AREAL COVERAGE/PROB
MENTION OF NON MEASURABLE FLURRIES WITH LK MI LIKELY SHUTTING
DOWN BEFORE LK HURON WITH TOKEN PROBABILISTIC MENTION CONTG INTO
EVENING FAR ERN CWA. CONTD/DEEPENING CAA TO AFFORD LITTLE THERMAL
RECOVERY TODAY. AND WITH CWA ON PERIPHERY OF WRN PERIPHERY OF 925
MB THERMAL TROF OVR LWR GRTLKS AND POTNL STRONG DECOUPLING
ENSUING OVERNIGHT HAVE GIVEN FAVOR TO THE COLDER SPECTRUM SIDE OF
GUIDANCE...IN LINE WITH PRIOR FCSTS.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 447 AM EDT FRI MAR 27 2015

VERY COLD CONDITIONS WILL BE AT THE ONSET OF THIS PERIOD SATURDAY
WITH A MODIFYING ARCTIC AIRMASS ACROSS THE AREA. EVEN WITH PLENTY
OF SUN SATURDAY...HIGHS SHOULD BE 15 TO 20 DEGREES BELOW NORMAL.
FAVOR THE WARMER GFS. THE NAM/MET HAS BEEN MUCH TOO COLD RECENTLY
WITH RETREATING ARCTIC AIRMASSES...ESPECIALLY WITH SUNNY TO
MOSTLY SUNNY SKIES. THE NEXT CHALLENGES ARE WITH AN UPPER LEVEL
TROF OF PACIFIC ORIGIN THAT SHOULD MOVE ACROSS THE FORECAST AREA
SUNDAY AFTERNOON. THERE WERE MAJOR DIFFERENCES BETWEEN THE GFS
AND THE NAM...WITH THE NAM CONTINUING TO HOLD ONTO THE COLD AIR
AN NOT MIX OUT THE LOWER LAYERS. GIVEN REASONABLE UPPER LEVEL
SUPPORT AND TIMING...HAVE RAISED PRECIPITATION CHANCES SUNDAY.
PRECIPITATION TYPES STILL A CHALLENGE AS EVEN THE WARMER GFS
SHOWING A MIX OF PRECIPITATION IS POSSIBLE. SO FOR THIS
PACKAGE...PLACED A RAIN AND SNOW MIX OVER NORTHERN AREAS WITH
JUST RAIN SOUTH. SUBSEQUENT SHIFTS WILL LIKELY NEED TO REFINE
THIS AREA.

OTHERWISE...FOR THE REST OF THE PERIOD...THE UPPER LEVEL PATTERN
SHOULD BECOME MORE HIGH ZONAL ALLOWING TEMPERATURES TO RISE ABOVE
NORMAL BY THE MIDDLE OF NEXT WEEK. TWO MORE UPPER LEVEL SYSTEMS
ARE EXPECTED TO BRING A CHANCE FOR MAINLY RAIN MONDAY NIGHT...AND
THEN JUST RAIN WEDNESDAY THROUGH THURSDAY AS TEMPERATURES BECOME
MILD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 648 AM EDT FRI MAR 27 2015

PRIMARILY VFR MET CONDS ANTICIPATED...SAVE FOR A FEW BRIEF PDS OF
UPR END MVFR /ABOVE FUELING AND ALT REQUIREMENTS/ NEXT FEW HOURS
ASSCOD WITH POCKETS OF DEEPER LAKE EFFECT MOISTURE/CONVECTION.
STEEPENING SFC BASED LAPSE RATES MIDDAY INTO AFTERNOON TO ALLOW
STRONGER NWRLY WINDS TO MIX TO SFC...THEN QUICKLY DECOUPLE THIS
EVENING AMID FAVORABLE SFC COOLING CONDS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MURPHY
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...MURPHY


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