Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 181755
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
155 PM EDT MON AUG 18 2014

.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 355 AM EDT MON AUG 18 2014

ACTIVE WEATHER REMAINS THE RULE FOR THIS FORECAST PERIOD AS
BOUNDARIES REMAIN IN THE AREA AND ANOTHER UPPER LEVEL SYSTEM WILL
IMPACT THE AREA TUESDAY INTO WEDNESDAY. LATER IN THE WEEK AN UPPER
LEVEL RIDGE WILL STRENGTHEN ACROSS THE MISSISSIPPI VALLEY...HELPING
TO PUSH TEMPERATURES BACK UP TO NEAR OR EVEN SLIGHTLY ABOVE SEASONAL
NORMALS...ALTHOUGH THE ELUSIVE 90 DEGREE MARK REMAINS OUT OF THE
FORECAST FOR INDIANAPOLIS.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1010 AM EDT MON AUG 18 2014

LATEST SURFACE REPORTS INDICATE VISIBILITIES HAVE RISEN ABOVE ONE
QUARTER MILE...SO HAVE ALLOWED THE DENSE FOG ADVISORY TO EXPIRE.
WILL HAVE TO CARRY SOME FOG FOR ANOTHER COUPLE OF HOURS OVER THE
NORTHWEST AND WEST CENTRAL ZONES...BUT THE FOG SHOULD BURN OFF
RATHER RAPIDLY AS MOISTURE LAYER IS QUITE SHALLOW.

OTHERWISE...NOT TOO IMPRESSED WITH PRECIPITATION POTENTIAL THIS
AFTERNOON WITH NO REAL TRIGGER OR FOCUS EVIDENT...BUT WITH AN
UNSTABLE AND WEAKLY CAPPED AIR MASS THIS AFTERNOON...CAN/T RULE OUT
THE DEVELOPMENT OF A FEW CONVECTIVE CELLS.

LOW LEVEL THICKNESSES SUGGEST THE HIGHS FOR TODAY MAY BE TOO COOL.
WILL RAISE THE HIGHS ABOUT A CATEGORY.

PREVIOUS DISCUSSION FOLLOWS.

WITH VISIBILITIES DROPPING AND FOG EXPANDING WILL HAVE TO ISSUE A
DENSE FOG ADVISORY ACROSS THE NORTHWEST. WILL CARRY THE ADVISORY
UNTIL 14Z.

LOW PRESSURE IS LOCATED ACROSS THE OHIO VALLEY THIS
MORNING...CENTERED NEAR LOUISVILLE. THIS WEAK LOW WILL CONTINUE TO
DRIFT UP THE OHIO VALLEY TODAY...BUT ONE OR MORE BOUNDARIES WILL
REMAIN SOMEWHERE ACROSS THE REGION...SO CANNOT GO ENTIRELY DRY
TODAY. HOWEVER...IN THE ABSENCE OF ANY UPPER LEVEL SUPPORT WILL
CARRY NO MORE THAN A SLIGHT CHANCE POP FOR ISOLATED
SHOWERS/STORMS...MAINLY DURING THE AFTERNOON HOURS.

ON TEMPS...WENT SLIGHTLY BELOW CONSENSUS NUMBERS AS IT HAS BEEN THE
TREND FOR THE PAST SEVERAL DAYS FOR MODEL TEMPS WITH RESPECT TO OBS.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 355 AM EDT MON AUG 18 2014

MAIN ISSUE IN THE SHORT TERM WILL BE THE SURFACE AND UPPER LEVEL
SYSTEM MOVING THROUGH THE GREAT LAKES LATE TONIGHT INTO WEDNESDAY.
THIS WILL NECESSITATE POPS REMAINING IN THE FORECAST FOR AT LEAST
A PORTION OF THE AREA EACH PERIOD...BUT CANNOT JUSTIFY MORE THAN A
20 TO 30 POP LATE TONIGHT AND TUESDAY NIGHT INTO WEDNESDAY. WILL
CONTINUE WITH HIGH CHANCE POPS ON TUESDAY...BUT IF MODELS REMAIN
CONSISTENT WITH THIS SYSTEM...WILL NEED TO INTRODUCE LIKELIES
SOON.

ON TEMPS...AGAIN STAYED WITH THE PATTERN OF GOING SLIGHTLY BELOW
CONSENSUS NUMBERS AS HAS BEEN THE RECENT TREND. CUT TEMPS ACROSS THE
NORTH ON TUESDAY AS PRECIP AND CLOUD COVER WILL LIKELY BE A FACTOR.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

ISSUED AT 155 PM EDT MON AUG 18 2014

ECMWF AND GFS DEPICT A WARM WEEKEND IN PLACE DURING THE PERIOD.
MODELS AGREE THAT A STRONG UPPER RIDGE WILL BE BUILDING ACROSS THE
MISSISSIPPI RIVER VALLEY AND OHIO VALLEY DURING THIS TIME
PERIOD...ALLOWING HEAT AND HUMIDITY TO BUILD FROM THE SOUTHWEST.
THIS SHOULD RESULT IN SOME OF THE WARMEST AIR OF THE SUMMER ACROSS
CENTRAL INDIANA. THROUGH SUNDAY THE BLOCKING RIDGE CONTINUES TO
PUSH APPROACHING SHORT WAVES FROM THE WEST WELL NORTH OF INDIANA.
MEANWHILE MODELS DO CONTINUE TO DEPICT VERY HIGH DEW POINTS IN THE
LOWER 70S. ECMWF ALSO SHOWS 700MB TEMPS THROUGH THE THE PERIOD AT
OR BELOW 10C...WHICH LEADS TO A QUESTIONABLE CAPPING SITUATION.
THUS WILL NEED TO INCLUDE CHANCES SEVERAL DAYS DURING THIS PERIOD
AS DIURNAL THUNDERSTORMS STILL APPEAR POSSIBLE.

HEAT LOOKS TO LESSEN ON MONDAY AS THE UPPER RIDGE ACROSS THE AREA
BEGINS TO FLATTEN. GFS AND ECMWF SHOW THE WARM ARE THEN BEING
PUSHED FARTHER SOUTH.

&&

.AVIATION /DISCUSSION FOR THE 181800Z TAFS/...

ISSUED AT 1245 PM EDT MON AUG 18 2014

PESKY MVFR FOG AND CIGS QUICKLY BURNING OFF EARLY THIS AFTERNOON
AS VISIBLE SATELLITE PICTURES SHOW A RAPID DETERIORATION OF THE
LOWER LEVEL CLOUD DECK. FORECAST SOUNDINGS SUGGEST CONVECTIVE
TEMPS IN THE LOWER 80S THIS AFTERNOON WILL LEAD TO SOME SCT-BKN
AFTERNOON DIURNAL CU.

HIGH DEW POINTS AND MINIMAL MIXING OVERNIGHT WILL ONCE AGAIN LEAD
TO FOG FORMATION OVERNIGHT AS THERE HAS BEEN LITTLE CHANGE IN THE
AIR MASS. THUS WILL TREND TOWARD IFR OR WORSE FOG AT BMG...LAF AND
HUF ONCE AGAIN. HEAT ISLAND EFFECT SHOULD KEEP IND AT MVFR FOG CONDITIONS.

ONCE FOG BURNS OFF AGAIN ON TUESDAY MORNING...A RETURN TO VFR
CONDITIONS IS EXPECTED WITH SCT-BKN CU DEVELOPMENT BY LATE MORNING.


&&

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

$$

SYNOPSIS...NIELD
NEAR TERM...NIELD/JAS
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JP

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