Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 231025
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
625 AM EDT WED JUL 23 2014

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 152 AM EDT WED JUL 23 2014

A QUICK MOVING COLD FRONT WILL SWEEP ACROSS CENTRAL INDIANA EARLY
THIS MORNING...REACHING THE OHIO RIVER BY THIS AFTERNOON. THIS
WILL RESULT IN ISOLATED SHOWER OR THUNDERSTORM CHANCES THIS MORNING
ACROSS CENTRAL INDIANA...FOLLOWED BY A DRY AND COOLER AND AFTERNOON.

HIGH PRESSURE FROM CANADA WILL THEN BUILD ACROSS THE HOOSIER STATE
TONIGHT THROUGH FRIDAY...PROVIDING DRY WEATHER WITH BELOW NORMAL
TEMPERATURES.

A SERIES OF UPPER LEVEL WEATHER DISTURBANCES ARE EXPECTED TO
PASS THROUGH INDIANA AND THE OHIO VALLEY THIS WEEKEND...BRINGING
CHANCES FOR SHOWERS AND STORMS.

&&

.NEAR TERM /TODAY/...

ISSUED AT 152 AM EDT WED JUL 23 2014

SURFACE ANALYSIS EARLY THIS MORNING SHOWS A COLD FRONT STRETCHING
FROM LOWER MICHIGAN ACROSS CENTRAL ILLINOIS TO CENTRAL MISSOURI.
RADAR SHOWS A THIN LINE OF THUNDERSTORMS ALONG THE FRONT OVER
SOUTHERN MICHIGAN AND NORTHEAST ILLINOIS...SLOWLY PROGRESSING
SOUTH WITH THE SOUTHERLY MOVEMENT OF THE FRONT. ACROSS CENTRAL
INDIANA SKIES WERE MOSTLY CLEAR WITH WARM SOUTHERLY SURFACE FLOW
AS SURFACE DEW POINT TEMPS WERE IN THE MIDDLE 60S TO NEAR 70.

MAIN FORECAST CHALLENGE TODAY WILL BE TIMING PRECIPITATION
CHANCES. GFS AND NAM SUGGEST FRONTAL BOUNDARY WILL BE NEAR OR JUST
SOUTH OF I-70 AT 12Z...AND WILL CONTINUE TO PUSH SOUTHWARD. RAPID
REFRESH SHOWS THE TSRA OVER MICHIGAN HOLDING TOGETHER YET
DIMINISHING IN INTENSITY AS THEY PROGRESS SOUTHWARD AT THIS
UNFAVORABLE DIURNAL TIME OF DAY. FORECAST SOUNDINGS AND TIME
HEIGHT FAIL TO SHOW DEEP SATURATION THIS MORNING...AND BEST
DYNAMICS APPEAR TO BE PUSHING EAST THROUGH THE GREAT LAKES. STILL
ENOUGH LOWER LEVEL MOISTURE AND SURFACE CONVERGENCE SHOW BE
PRESENT ALONG THE FRONT TO KEEP CHANCES IN PLACE ALONG THE FRONT
MAINLY DURING THE MORNING HOURS. BEST CHANCES FOR TODAY WILL BE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA WHERE THE FRONT
REACHES LAST...WITH LESSER TO NO POPS ACROSS THE NORTH WHERE THE
FRONT SHOULD HAVE ALREADY DEPARTED. GIVEN THE EXPECTED CLOUDS IN
THE AREA TODAY AND THE BEGINNING OF COLD AIR ADVECTION IN THE WAKE
OF THE FRONT WILL TREND TEMP SO AT OR BELOW MAVMOS. BY LATE
AFTERNOON SURFACE BOUNDARY SHOULD BE WELL SOUTH OF THE FORECAST
AREA AND A DRY FORECAST WILL BE IN PLACE BY THEN.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...

ISSUED AT 152 AM EDT WED JUL 23 2014

MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND OVERALL. A QUIET END TO THE WORK WEEK LOOKS IN STORE
AS TONIGHT THROUGH FRIDAY WILL BE DOMINATED BY HIGH PRESSURE
SETTING ACROSS THE REGION FROM CENTRAL CANADA. THIS COOL AND DRY
CONTINENTAL AIR MASS WILL PROVIDE COOLER THAN NORMAL AND DRY
WEATHER CONDITIONS THROUGH FRIDAY. FORECAST SOUNDINGS THROUGH THE
PERIOD SHOW A DRY COLUMN ALONG WITH UNREACHABLE CONVECTIVE
TEMPERATURES. MID LEVELS THROUGH THE PERIOD REMAIN DRY WITH
SUBSIDENCE. THE FLOW ALOFT THROUGH THE PERIOD REMAINS QUICK AND
FRONT THE NORTHWEST...THUS A FEW PASSING CI WILL BE POSSIBLE FROM
TIME TO TIME. FORECAST SOUNDINGS CONFIRM THAT WITH OCCASIONAL
SATURATION APPEARING ALOFT. THUS WILL TREND TOWARD PARTLY CLOUDY
SKIES DURING THIS PERIOD ALONG AT OR BELOW MAVMOS.

BY FRIDAY NIGHT FLOW ALOFT REMAINS PROGRESSIVE AND FROM THE
NORTHWEST. GFS HINTS AT A SHORT WAVE ARRIVING IN THE AREA DURING
THE EVENING HOURS...WHILE THE NAM IS A BIT QUICKER. FORECAST
SOUNDINGS BEGINNING TO HINT AT A TOP DOWN SATURATION...AND
SOUTHERLY AND MORE HUMID FLOW WILL HAVE ARRIVED. WILL INCLUDE SOME
CHC POPS FOR NOW AT THIS TIME ON FRIDAY NIGHT...HOWEVER TIMING AND
PROGRESSION WILL REMAIN HIGHLY CHANGEABLE AT A PERIOD THIS FAR WAY
IN THE WAKE OF DEPARTING HIGH. WILL TREND TEMPS A BIT WARMER THAN
MAVMOS ON FRIDAY NIGHT GIVEN EXPECTED CLOUDS AND POSSIBLE RAIN.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 220 AM EDT WED JUL 23 2014

MODELS ARE SIMILAR WITH THE OVERALL PATTERN IN THE LONG TERM SO USED
A BLEND. ALLBLEND INITIALIZATION HAD SOME PROBLEMS SO DEVIATED FROM
IT WHEN NECESSARY.

THROUGH THE LONG TERM ANOTHER UPPER TROUGH WILL DEEPEN ACROSS THE
EASTERN USA. THIS WILL RESULT IN A COOLING TREND AND FREQUENT
CHANCES FOR RAIN.

DURING THE WEEKEND A COUPLE OF AREAS OF LOW PRESSURE WILL MOVE
THROUGH THE REGION BRINGING COLD FRONTS WITH THEM. UNCERTAINTIES IN
TIMING THAT FAR OUT PRECLUDE GOING ANY HIGHER THAN CHANCE CATEGORY
POPS FOR ANY ONE PERIOD.

ON MONDAY AS THE UPPER TROUGH DIGS ANOTHER SURFACE TROUGH WILL BRING
LOW CHANCES FOR RAIN. AFTER THAT THERE APPEARS TO BE A BRIEF BREAK
IN RAIN CHANCES AS HIGH PRESSURE SNEAKS IN FROM THE WEST.

&&

.AVIATION /DISCUSSION FOR THE 231200 TAF ISSUANCE/...
ISSUED AT 625 AM EDT WED JUL 23 2014

SCATTERED CONVECTION THROUGH THE MORNING HOURS WITH A PERIOD OF MVFR
CEILINGS OUTSIDE OF CONVECTION...THEN VFR THIS AFTERNOON ON.

RADAR SHOWS SCATTERED CONVECTION DEVELOPING BEHIND AN OUTLFOW
BOUNDARY MOVING ACROSS THE AREA. FEEL THAT CONVECTION SHOULD BEGIN
TO WANE AS IS TYPICAL FOR NEAR SUNRISE SO FOR NOW WILL JUST HAVE
VCTS.

COLD FRONT WILL MOVE THROUGH THIS MORNING SHIFTING WINDS TO THE
NORTHWEST. MODELS SHOWING SOME ADDITIONAL CONVECTION THIS MORNING
WITH THE FRONT...BUT MOST OF IT SHOULD BE SOUTH OF THE SITES. WILL
USE VCSH. NUMEROUS MVFR CEILINGS ASSOCIATED WITH THE FRONT...SO WILL
INCLUDE A PERIOD OF MVFR THIS MORNING.

DRIER AIR WORKS IN THIS AFTERNOON AND RETURNS CONDITIONS TO VFR.

&&

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

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...50
AVIATION...50

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