Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 270904
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
504 AM EDT WED AUG 27 2014

.SYNOPSIS...
ISSUED AT 500 AM EDT WED AUG 27 2014

A COLD FRONT WILL SINK SLOWLY SOUTH TODAY AND TONIGHT...BRINGING
COOLER AND LESS HUMID CONDITIONS. HIGHS TODAY WILL RANGE FROM THE
UPPER 70S ACROSS LOWER MICHIGAN TO THE MIDDLE 80S INTO CENTRAL
INDIANA. LOWS TONIGHT WILL BE IN THE 50S. RAIN CHANCES WILL
RETURN FOR THE WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT WED AUG 27 2014

COOL FRONT WAS LOCATED ACROSS SOUTHERN PORTIONS OF THE AREA. WHILE
RATHER DIFFUSE APPEARS TO BE JUST ENOUGH CONVERGENCE WITH IT THAT
WIDELY SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ALONG AND SOUTH
OF ROUTE 24. THESE HAVE BEEN DIMINISHING BUT WITH FRONTAL BOUNDARY
STILL IN THE AREA FOR AT LEAST THE MORNING WILL GO WITH SLGT CHC
POPS IN THE FAR SOUTH BUT END ALL POPS BY 18Z. A FEW SHOWERS AND
STORMS ALSO EXTENDED BACK INTO PORTIONS OF IOWA. WHILE THESE ARE
HEADING EAST THINK THEY SHOULD REMAIN WEST AND SOUTH OF THE AREA AND
TRAVEL ALONG THE FRONT. IF THE FRONT STALLS OUT...THEN COULD NEED TO
EXPAND POPS INTO THE AFTERNOON HOURS. NORTH OF THE FRONT...MOSTLY
CLEAR SKIES HAVE ALLOWED FOR PATCHY FOG...DENSE AT TIMES IN SEVERAL
AREAS. VISIBILITIES HAVE BEEN HIGHLY VARIABLE WITH THE SHALLOW
NATURE OF THE FOG. FOG WILL LINGER THROUGH SUNRISE BUT SHOULD BURN
OFF QUICKLY AS SLIGHTLY DRIER AIR CONTINUES TO WORK IN FROM THE
NORTH. TEMPERATURES TODAY WILL BE TRICKY ESPECIALLY SOUTH WITH
LOCATIONS NORTH OF THE FRONT LIKELY TO REACH THE UPPER 70S TO LOWER
80S. ALONG AND SOUTH OF THE FRONT...HIGHS COULD CLIMB INTO THE MID
TO UPPER 80S...IF ENOUGH SUNSHINE IS REALIZED. UPSTREAM CLOUD COVER
WAS SOMEWHAT LACKING. HOWEVER WON`T TAKE MUCH TO GET CU DEVELOPMENT
GOING ONCE AGAIN THAT COULD KEEP TEMPS DOWN. WILL STAY CONSERVATIVE
AND NUDGE HIGHS A DEGREE OR SO UPWARDS.

TONIGHT SHOULD BE QUIETER WITH BOUNDARY JUST FAR ENOUGH SOUTH TO
KEEP THE AREA DRY AS HIGH PRESSURE WINS THE STRUGGLE FROM THE
NORTH...AT LEAST BRIEFLY. LIGHT NE FLOW SHOULD USHER IN SOME VERY
PLEASANT AIR TO THE AREA...ESPECIALLY NORTHERN HALF OR SO. HAVE
LOWERED OVERNIGHT LOWS MORE THAN PREVIOUS GRIDS WITH LOWS IN THE MID
50S NORTH TO NEAR 60 SOUTH. FAVORED DRAINAGE AREAS HAVE BEEN LOWERED
A BIT MORE (BENTON HARBOR AREA INTO THE LOWER 50S).

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 500 AM EDT WED AUG 27 2014

CHALLENGES STILL REVOLVE AROUND POPS GOING INTO HOLIDAY WEEKEND.
SOME HIR CONFIDENCE IN CARVING OUT GREATER AREA/CONFIDENCE FOR DRY
RESPITE THU/THU NIGHT. SLOWED EASTWARD PROGRESSION OF SURFACE RIDGE
THROUGH CENTRAL TO LOWER GREAT LAKES...AND LOW AMPLITUDE MID
TROPOSPHERIC SHORTWAVE RIDGING ALOFT...PENDING CRISTOBAL NORTHWARD
RETREAT INTO MID LATITUDE WESTERLIES. UPSTREAM OF TEMPO BLOCKING
PATTERN EXTREMELY RICH PWAT/THETA-E REGIME THEN POOLS FROM EASTERN
NE INTO ERN KY/ERN TN. STRONG EVAPOTRANSPIRATIVE PROCESSES THROUGH
CORN BELT ALONG WITH N-NEWD DRAW OF MONSOONAL MOISTURE BY INTENSE
INTERMOUNTAIN VORTEX MOVING EWD INTO CENTRAL PLAINS...SHOULD PUSH
UPSTREAM SFC DPS TO MID 70S BY FRI. SOME CONCERN THAT SUBTROPICAL
RIDGE ASSERTION ACROSS SOUTHEAST UNITED STATES MAY LEAD TO BEST
THETA-E/STORM TRACK CORRIDOR WELL NORTHWEST OF CWA ON FRIDAY AS THE
SHORTWAVE BEGINS NORTHEAST LIFT OUT AND DECAY. SIDED WITH HIGHEST
CONVECTIVE CHANCES/QPF POTENTIAL SAT INTO SUN...AS NORTHERN STREAM
WAVE /ASSOCIATED WITH DEEP PVU ANOMALY NEAR 50N/145W/ RACES INTO
UPPER MIDWEST SAT AND SHUNT MOISTURE BELT AND STRENGTHENED DEEP
SW-WSWLY FLOW. SECOND SHORTWAVE TO LIKELY FOSTER FRONTOGENETIC WAVE
ALONG LATENT FRONTAL BOUNDARY WITH POTENTIAL FOR REPETITIVE FORWARD
PROPAGATING CONVECTIVE SEGMENTS THROUGH THE WEEKEND. WHILE MESOSCALE
DETAILS STILL MULTIPLE DAYS FROM BEING RESOLVED...WILL STRESS
GENERAL FLOODING POTENTIAL IN HWO GIVEN STRONG ASSOCIATION TO AN
INGREDIENTS BASED CONCEPTUAL MODEL WITH PWAT 2-2.25 INCHES...DEEP
WARM CLOUD LAYER DEPTH GTE 12KFT AND POSSIBLE TRAINING GIVEN DEEP
LAYER PARALLEL TO SURFACE BOUNDARY FLOW. CURRENT FALLING LIMB
HYDROGRAPHS OF MAINSTEM RIVERS IN WABASH/MAUMEE BASINS ALONG WITH
ELEVATED STREAMFLOW CONDITIONS AND RELATIVELY LOW HEADWATERS FLOOD
GUIDANCE SUGGESTS CAUTION. LESSER POPS DYS 5-7 THOUGH UNABLE TO
EASILY PULL AWAY FROM BLENDED CONSENSUS AS BROAD LONGWAVE TROF WITH
MULTIPLE PERTURBATIONS APPEARS TO REMAIN A SEMI PERMANENT FIXTURE
THROUGH NORTHERN TIER CONUS...WELL INTO MIDDLE NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 142 AM EDT WED AUG 27 2014

FOG/STRATUS WILL BE THE MAIN CHALLENGE FOR THE NEXT 6 TO 9 HOURS
AS STRUGGLE BETWEEN DRIER AIR AND MOIST BOUNDARY LAYER CONTINUES.
CIGS AND VSBYS HAVE BEEN HIGHLY VARIABLE AT KSBN AND SUSPECT THIS
WILL CONTINUE THROUGH THE NIGHT. AS OF WRITING THIS VSBYS RANGED
FROM 4 SM DOWN TO 3/4SM WHICH IS IMPOSSIBLE TO CAPTURE IN TAFS.
HAVE TRIED TO GO WITH WHAT WILL BE THE MOST PREDOMINANT VSBYS AND
CIGS BUT PILOTS WILL NEED TO MONITOR FOR LOCALLY VARIABLE
CONDITIONS AS FOG HAS BEEN RATHER SHALLOW IN NATURE. IF COVERAGE
EXPANDS THEN WILL NEED TO AMEND TAFS. AT KFWA...FOG AND STRATUS
WILL ARRIVE A BIT LATER AND MAY NOT BE AS MUCH OF AN ISSUE SO HAVE
BEEN SLIGHTLY MORE CONSERVATIVE THERE.

AFTER SUNRISE...VFR CONDITIONS SHOULD PREVAIL AS HIGH PRESSURE
BUILDS IN FROM THE NORTH FOR THE REMAINDER OF THE PERIOD WITH A
NORTH TO NORTHEAST WIND.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...FISHER


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