Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 290555
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
155 AM EDT TUE JUL 29 2014

.SYNOPSIS...
ISSUED AT 143 AM EDT TUE JUL 29 2014

COOLER AND LESS HUMID CONDITIONS WILL PREVAIL THROUGH MUCH OF THE
UPCOMING WEEK AS LOW PRESSURE REMAINS WELL NORTH OF THE REGION.
THERE IS A SMALL CHANCE FOR SHOWERS AND POSSIBLY EVEN A RUMBLE OF
THUNDER TUESDAY AFTERNOON AS A WEAK DISTURBANCE MOVES THROUGH THE
REGION. LOWS TONIGHT WILL DROP INTO THE UPPER 40S TO LOWER
50S. HIGHS ON TUESDAY WILL CLIMB BACK INTO THE LOWER TO MIDDLE
70S.

&&

.UPDATE...
ISSUED AT 822 PM EDT MON JUL 28 2014

VORT MAX DROPPING ACROSS SOUTHERN LAKE HURON THIS EVENING HAS
ALLOWED FOR LOW CLOUDS TO PERSIST PAST DIURNAL PEAK HEATING...BUT
SHOULD DIMINISH OVER NEXT FEW HOURS AS THIS VORT MAX SLIDES INTO
SOUTHEAST ONTARIO. NEXT UPSTREAM VORT MAX ACROSS EAST CENTRAL
WISCONSIN WILL DROP INTO THE SOUTHERN GREAT LAKES LATER THIS
EVENING...WITH SOME INDICATIONS THAT LOW CLOUDS MAY TRY TO BUILD
BACK INTO FAR NORTHWEST LOCATIONS LATE EVENING/OVERNIGHT. HAVE
MADE MINOR TWEAKS TO SKY COVER TO ACCOUNT FOR CURRENT TRENDS. ONLY
OTHER CHANGE THAT MAY BE CONSIDERED FOR EVENING UPDATE IS SLIGHTLY
COOLER MINS...WITH SOME LOCALIZED UPPER 40S NOT OUT OF THE
QUESTION GIVEN IDEAL RADIATIONAL COOLING CONDITIONS AND DRY LOW
LEVEL AIR MASS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 336 PM EDT MON JUL 28 2014

A PLEASANT BUT COLD PERIOD WILL BE IN STORE AS POCKET OF COLDER AIR
FILTERS INTO THE REGION. SKIES SHOULD BECOME MOSTLY CLEAR THIS
EVENING INTO THE OVERNIGHT HOURS ALLOWING FOR A RAPID DROP IN TEMPS.
LATER TONIGHT...A DISTURBANCE WILL ROTATE THROUGH THE FLOW AND BRING
AN INCREASE IN MID CLOUDS. CHALLENGE COMES WITH CHANCES FOR
SHOWERS/ISOL THUNDER STARTING MID MORNING TUES INTO THE AFTERNOON
HOURS. 500 MB TEMPS GET TOWARDS -16 C IN THE NORTH AND EAST...BUT
OVERALL LAPSE RATES ABOVE 850 MB RATHER POOR. 1000-850 MB LAPSE
RATES NOT BAD AND ENOUGH TO GET CU POPPING AND MAYBE SOME ISOLATED
TO AT BEST SCT SHOWERS. MODELS VARY...BUT DO SHOW POTENTIAL FOR 1KM
MIXED LAYER CAPE BETWEEN 400 J/KG (SREF) AND 1000 J/KG (NAM). THIS
WOULD BE SUFFICIENT FOR AT LEAST A MENTION OF THUNDER. HAVE LEFT AT
SLGT CHC FOR NOW. HIGHS WILL CLIMB INTO THE LOWER 70S.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 336 PM EDT MON JUL 28 2014

STEADY STATE AMPLIFIED FLW REGIME XPCD TO CONT THROUGH THIS
PD...ANCHORED OUT WEST BY UPR RIDGE EXTNDG NWD THROUGH SWRN CANADA
AND EAST BY DEEP UPR LOW CNTRD NR JAMES BAY. AS A RESULT XPC CONTD
DRY NWRLY LL FLW AND PLEASANT TEMPERATURES THROUGH THE PD.

IN LIGHT OF CONSENSUS POSITIONING OF MID LVL TROUGH AND DRY AIRMASS
RESIDING OVR THE LAKES THREW OUT ALLBLEND POP GUIDANCE AS
UNSEASONABLE COOL LAKE COMPOSITE THETA-E SINK CONTS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 143 AM EDT TUE JUL 29 2014

VFR CONDITIONS EXPECTED TO PERSIST THROUGH THIS FORECAST PERIOD.
UPSTREAM IMPULSE COMBINED WITH EXTREMELY COLD MID TROPOSPHERIC
PROFILES SHOULD EASILY GENERATE CU FIELD COINCIDENT WITH MID/LATE
AM SURFACE HEATING. PRESENCE OF MOISTURE PER AMDAR SOUNDINGS IN
850-740MB LAYER AS WELL AS DEGREE OF SURFACE TO 5H THERMAL
DIFFERENTIALS SUGGEST EVEN POTENTIAL FOR SCT SHRA/ISOLD TSRA WITH
PEAK HEATING. AT PRESENT HAVE ONLY ADDED MENTION VCSH TO KFWA PER
TIMING OF IMPULSE AND SLIGHTLY GREATER INSTABILITY/LOW LEVEL
CONVERGENCE SIGNALS PRESENTING WELL INLAND OF LAKE MICHIGAN.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT UNTIL 4 AM CDT EARLY THIS MORNING FOR
     INZ003.

MI...BEACH HAZARDS STATEMENT UNTIL 5 AM EDT EARLY THIS MORNING FOR
     MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
     LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MURPHY
SHORT TERM...FISHER
LONG TERM...T
AVIATION...MURPHY


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