Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 191904
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
204 PM EST FRI DEC 19 2014

.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 205 PM EST FRI DEC 19 2014

A HIGH PRESSURE SYSTEM WILL DOMINATE INDIANA WEATHER INTO SUNDAY AS
ITS CENTER SHIFTS FROM THE MID MISSISSIPPI VALLEY TO NEW ENGLAND.

FROM MONDAY INTO THURSDAY THE MOST IMPORTANT INFLUENCE ON HOOSIER
WEATHER IS GOING TO BE A LOW PRESSURE SYSTEM. THIS SYSTEM IS
FORECAST TO START DEVELOPING OVER THE PLAINS LATE IN THE WEEKEND. IT
IS EXPECTED TO HEAD EAST...GAINING STRENGTH AS IT DOES.

BY TUESDAY MORNING LOW PRESSURE WILL HAVE ARRIVED IN THE UPPER
MISSISSIPPI VALLEY. BY WEDNESDAY IT IS EXPECTED TO BE
VERY...VERY...STRONG AND CENTERED OVER SOUTHERN ONTARIO. LATE
CHRISTMAS DAY ITS INFLUENCE ON INDIANA WILL WEAKEN AS IT HEADS INTO
QUEBEC.

FRIDAY OUR WEATHER IS PREDICTED COME UNDER THE INFLUENCE OF ANOTHER
LOW PRESSURE SYSTEM COMING FROM THE PLAINS.


&&

.NEAR TERM /TONIGHT AND SATURDAY/...

ISSUED AT 205 PM EST FRI DEC 19 2014


THE MAIN ISSUE IS CLOUDINESS AND ITS AFFECT ON TEMPERATURES.

CLEARING DEVELOPED OVER MUCH OF ILLINOIS AND SOUTHWEST INDIANA
TODAY. HOWEVER LATEST SATELLITE PICTURES SHOW STRATUS MOVING TOWARD
THE CLEAR AREA FROM THE NORTHEAST...AND CLOUDS WITH A SHORT WAVE
APPROACHING FROM THE SOUTHWEST. TONIGHT SHOULD BE CLOUDY.

THE MODELS AGREE BY LATE SATURDAY THE SHORT WAVE IS GOING TO BE TO
OUR EAST AND THE ATMOSPHERIC COLUMN WILL BE DRYING. THEY ALSO AGREE
WE WILL BE UNDER AN INVERSION ON THE EAST SIDE OF A RIDGE WITH 925
MILLIBAR RELATIVE HUMIDITIES 70 PERCENT OR HIGHER.

SUCH A PATTERN FAVORS STRATUS. SATURDAY IS GOING TO BE ANOTHER
MOSTLY CLOUDY DAY. THE SOUTHWEST MIGHT GET A LITTLE SUN IN THE
AFTERNOON.

CLOUDS ARE GOING TO DAMPEN DIURNAL TEMPERATURES CHANGES. MAV AND MET
MINIMUMS ARE CLOSE OVERNIGHT. THEY LOOK OK CONSIDERING WHAT WE HAVE
NOW. THERE HAS BEEN A STRONG WARM BIAS IN SIMILAR SITUATIONS WITH
DAYTIME TEMPERATURES LATELY. THE COOLER MET TEMPERATURES ARE
PREFERRED SATURDAY. POSSIBLY EVEN THEY WILL BE TOO WARM.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...

ISSUED AT 205 PM EST FRI DEC 19 2014

ALL THE MODELS AGREE IT WILL BE DRY THROUGH SUNDAY NIGHT WITH A
CHANCE OF RAIN MONDAY AS A WARM FRONT DEVELOPS OVER THE AREA. CLOUDS
AND TEMPERATURES ARE THE MAIN FORECAST ISSUES.

SATURDAY NIGHT WE SHOULD MOVE TO THE WEST SIDE OF A WEAK SURFACE
RIDGE. THIS WILL GIVE A CHANCE TO SCOUR OUT THE LOW LEVEL MOISTURE
THAT HAS BEEN PERSISTENT RECENTLY. HOWEVER AS THAT HAPPENS WARM
ADVECTION ALOFT SHOULD CAUSE MID LEVEL CLOUDINESS. WE CAN EXPECT
CLOUDY WEATHER TO CONTINUE.

THE RESULT IS GOING TO BE DAMPENED TEMPERATURE CHANGES...ALTHOUGH
NOT QUITE TO EXTENT AS EARLIER IN THE WEEK SINCE THE CLOUDS SHOULD
BE MID LEVEL AS OPPOSED TO LOW LEVEL. GUIDANCE TEMPERATES MAY BE
OK SATURDAY NIGHT CONSIDERING WHAT DAYTIME READINGS WILL BE. AFTER
THAT THE COOLER MET LOOKS BETTER FOR SUNDAY AND THE WARMER MAV
FOR SUNDAY NIGHT.

ON MONDAY STRONG WARM ADVECTION WILL COUNTERACT THICKENING CLOUDS AND
POSSIBLY RAIN AS A WARM FRONT FORMS OVER US. TEMPERATURES COULD
SURGE INTO THE 50S OR STAY IN THE 40S DEPENDING ON HOW THINGS COME
TOGETHER. A CONSENSUS BETWEEN THE MEX AND THE EUROPEAN GUIDANCE
WILL BE USED.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 333 AM EST FRI DEC 19 2014

A MUCH MORE ACTIVE AND UNSETTLED WEATHER PATTERN SETTING UP FOR
THE HOLIDAY WEEK...HIGHLIGHTED BY A POTENTIAL LARGE STORM SET TO
IMPACT THE GREAT LAKES AND OHIO VALLEY TUESDAY THROUGH CHRISTMAS.
LOTS TO TALK ABOUT THIS MORNING.

STRONG RIDGING ALOFT SET TO DEVELOP OFF THE PACIFIC COAST AT THE
BEGINNING OF THE EXTENDED...AND THIS WILL PROMPT FALLING HEIGHTS
DOWNSTREAM EAST OF THE ROCKIES AS THE UPPER LEVEL FLOW AMPLIFIES.
QUITE A BIT OF ENERGY COURTESY OF A VERY STRONG UPPER LEVEL JET
PLOWING INTO THE PACIFIC NORTHWEST SET TO DIVE INTO THE EXPANDING
TROUGH AND LEAD TO PHASING WITH SOUTHERN STREAM JET ENERGY. AT THE
SURFACE...LOW PRESSURE SET TO TRACK OUT OF THE NORTHERN PLAINS ON
MONDAY WITH A TRAILING COLD FRONT. MOISTURE WILL BE DRAWN NORTH
INTO THE REGION AS THE FRONT AND SURFACE WAVE APPROACH...WITH RAIN
BECOMING LIKELY BY MONDAY NIGHT.

RAIN WILL CONTINUE ON TUESDAY AS THE AFOREMENTIONED SURFACE WAVE
TRACKS INTO THE GREAT LAKES. A SECOND AREA OF LOW PRESSURE SET TO
ORGANIZE OVER THE NORTHWEST GULF/LOWER MISSISSIPPI VALLEY DURING
THE DAY TUESDAY AS THE SUBTROPICAL JET ENERGY LINKS UP WITH THE
NORTHERN STREAM JET. THE UPPER TROUGH WILL QUICKLY GAIN A NEGATIVE
TILT WITH RAPID CYCLOGENESIS COMMENCING TUESDAY NIGHT INTO EARLY
WEDNESDAY.

INDIVIDUAL MODEL RUNS THIS MORNING DIFFER WITH REGARDS TO TIMING
AND LOCATION OF THE PHASING SURFACE WAVE...BUT THE KEY TAKEAWAY IS
THAT MODEL CONSENSUS INCLUDING BULK OF THE ENSEMBLE RUNS ALL SHOW
THE DEEPENING SYSTEM OVER THE EASTERN PART OF THE COUNTRY.
CONFIDENCE CONTINUES TO GROW IN A HIGH IMPACT SYSTEM FOR THE
REGION FROM LATE TUESDAY INTO EARLY THURSDAY...BUT THE DETAILS ARE
YET TO BE IRONED OUT AND LIKELY WILL NOT BE FOR ANOTHER FEW DAYS
UNTIL THE INTENSE UPPER JET ENERGY APPROACHING THE PACIFIC
NORTHWEST IS PROPERLY SAMPLED BY THE UPPER AIR NETWORK. AT THIS
POINT...HAVE LEANED IN THE DIRECTION OF THE GLOBAL MODELS WHICH
FAVOR A FASTER PHASING...BUT ALL POSSIBILITIES REMAIN OPEN AT THIS
EARLY STAGE UNTIL GREATER MODEL CONSENSUS CAN BE REACHED.

WITH ALL OF THIS BEING SAID...ANTICIPATE RAIN MIXING WITH THEN
CHANGING TO SNOW TUESDAY NIGHT INTO WEDNESDAY. FAR TOO EARLY TO
TALK POTENTIAL ACCUMULATIONS WEDNESDAY THROUGH EARLY THURSDAY...BUT
THESE LOOK RELATIVELY LIGHT AT THIS POINT. WIND IS LIKELY TO BE A
MORE SIGNIFICANT FACTOR CONSIDERING THE PROGGED INTENSITY OF THE
LOW TO SUB-980MB LEVELS AND POSSIBLY LOWER BY EARLY THURSDAY. EVEN
IF SNOW AMOUNTS ARE LIGHT...WIND DRIVEN SNOW SHOWERS COULD CREATE
TRAVEL DIFFICULTIES AT THE WORST POSSIBLE TIME...CHRISTMAS EVE
INTO EARLY CHRISTMAS MORNING. THOSE WITH TRAVEL PLANS DURING THIS
TIME PERIOD ARE ENCOURAGED TO STAY TUNED IN THE COMING DAYS. AND THIS
MAY JUST BE THE START...AS AN ACTIVE PATTERN LIKELY PERSISTS BEYOND
THE 7 DAY INTO NEXT WEEKEND.

&&

.AVIATION /DISCUSSION FOR THE 19/1800Z TAF ISSUANCE/...

ISSUED AT 1156 AM EST FRI DEC 19 2014

A BRIEF PERIOD OF CLEARING OVER KHUF AND KBMG WILL COME TO AN END
WITHIN THE NEXT FEW HOURS AS PERSISTENT STRATUS FILTERS BACK INTO
THE TAF SITES. AN INVERSION WILL CONTINUE TO TRAP MOISTURE NEAR
THE SURFACE...RESULTING IN MVFR CONDITIONS FOR DURATION OF TAF
PERIOD.  WINDS WILL BE LIGHT AND NORTHERLY.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....RYAN
AVIATION...TDUD

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