Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 180221
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1019 PM EDT FRI APR 17 2015

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

&&

.SYNOPSIS...
ISSUED AT 151 PM EDT FRI APR 17 2015

A PLEASANT AND QUIET START TO THE WEEKEND IS EXPECTED ACROSS
CENTRAL INDIANA BEFORE ENDING ON A STORMY NOTE.

HIGH PRESSURE OVER THE REGION TONIGHT IS EXPECTED TO SLOWLY DRIFT
EAST TONIGHT. THIS WILL RESULT IN DRY AND PLEASANT WEATHER BOTH
TODAY AND SATURDAY.

A LOW PRESSURE SYSTEM IS EXPECTED TO ARRIVE IN INDIANA FROM THE
LOWER MISSISSIPPI RIVER VALLEY ON SUNDAY. THIS WILL BRING RAIN
CHANCES TO OUR STATE LATE SATURDAY NIGHT AND RAIN WILL BE LIKELY
ON SUNDAY.

COOLER NORTHWEST FLOW WILL BE IN PLACE AS THE LOW DEPARTS TO THE
NORTHEAST ON MONDAY. A FEW LINGERING SHOWERS WILL BE POSSIBLE AS
THE NEXT WORK WEEK RESUMES.

&&

.NEAR TERM /TONIGHT/...

ISSUED AT 930 PM EDT FRI APR 17 2015

DEW POINT DEPRESSIONS WERE HIGH ACROSS THE FORECAST AREA THIS
EVENING. DEW POINTS THEMSELVES ARE LOWER THAN LAST NIGHT. IN
ADDITION...THE SREF ENSEMBLE CHANCES OF VISIBILITY LESS THAN 3 MILES
AND CEILINGS LESS THAN 1000 FEET WERE 5 PERCENT OR LESS AND ONLY
ACROSS OUR SOUTHWESTERN COUNTIES...WHERE DEW POINTS WERE HIGHEST.
SO...WILL NOT GO ANYMORE PESSIMISTIC THAN PATCHY FOG FOR THE
OVERNIGHT.

PREVIOUS DISCUSSION FOLLOWS...

ISSUED AT 151 PM EDT FRI APR 17 2015

SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS BROAD...POORLY
ORGANIZED HIGH PRESSURE IN PLACE OVER INDIANA. SATELLITE SHOWED
PLENTY OF HIGH CLOUD ACROSS THE STATE AMID THE QUICK W-NW FLOW
ALOFT. WATER VAPOR SHOWED AN UPPER LOW NEAR THE FOUR CORNERS AND A
STREAM OF TROPICAL MOISTURE WAS STREAMING ACROSS TEXAS AND INTO
THE CENTRAL PLAINS AHEAD OF THIS SYSTEM. DEW POINT TEMPS ACROSS
CENTRAL INDIANA REMAINED IN THE MID 40S TO LOWER 50S.

MAIN FORECAST CHALLENGE TONIGHT WILL BE TEMPS AND FOG.

GFS AND NAM CONTINUE TO SUGGEST THAT UPPER RIDGING AHEAD OF THE
APPROACHING LOW WILL BUILD ACROSS CENTRAL INDIANA TONIGHT AND
INTO SATURDAY. TIME HEIGHT SECTIONS SHOW A DRY COLUMN TONIGHT.
MODELS ALSO SUGGEST NEUTRAL ADVECTION OVERNIGHT. WITH DEW POINT
TEMPS IN THE MIDDLE 40S...WILL AIM FOR LOW AT OR ABOVE
PERSISTENCE. WITH DEW POINT DEPRESSIONS LESS THAN 2...ESPECIALLY
IN RURAL AREAS...WILL MENTION PATCHY DENSE FOG FOR NOW...BUT IF
CONDITIONS REMAIN FAVORABLE...EVENING SHIFT CAN UPGRADE.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...

ISSUED AT 151 PM EDT FRI APR 17 2015

MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND. MAIN FORECAST CHALLENGE WILL BE POPS ON SUNDAY.

A GLORIOUS SPRING DAY LOOKS IN STORE FOR SATURDAY AS STRONG
RIDGING REMAINS IN PLACE ALOFT...PROVIDING GOOD SUBSIDENCE.
FORECAST SOUNDINGS AND TIME HEIGHTS REMAIN RATHER DRY AS THE
SURFACE SLOWLY DRIFTS EAST. CONVECTIVE TEMPERATURES ARE REACHABLE
IN THE MIDDLE 70S ON SATURDAY...THUS SOME CU WILL BE POSSIBLE.
THUS WILL AIM FOR A MOSTLY SUNNY DAY WITH HIGHS NEAR
MAVMOS...WHICH APPEAR ON THE MARK.

CLOUDS ARE EXPECTED TO INCREASE ON SATURDAY NIGHT AS THE LOW
PRESSURE SYSTEM AND UPPER LOW OVER THE SOUTHERN PLAINS BEGINS TO
MOVE TOWARD INDIANA. FORECAST SOUNDING ON SATURDAY NIGHT LOOK TO
REMAIN DRY IN THE LOWER LEVELS...HOWEVER UPPER LEVELS LOOK TO
SATURATE...INDICATING INCREASING CLOUDS AHEAD OF THE APPROACHING
SYSTEM. THUS WILL TREND TOWARD BECOMING MOSTLY CLOUDY ALONG WITH
TEMPS AT OR ABOVE MAVMOS GIVEN THE INCREASING CLOUDS.

RAIN LOOKS LIKE A GOOD BET ON SUNDAY. GFS AND NAM DEPICT A SURFACE
LOW MOVING ACROSS THE STATE THROUGH THE DAY. MEANWHILE AN
NEGATIVELY TILTED TROUGH ALOFT WORKS ACROSS THE STATE...PROVIDING
FORCING. GFS 300K ISENTROPIC SURFACE SHOWS EXCELLENT UP GLIDE WITH
SPECIFIC HUMIDITIES OVER 6 G/KG. FORECAST SOUNDINGS ALSO SHOW DEEP
SATURATION AS THESE FEATURES PASS. THUS WITH ALL OF THESE
FEATURES...WILL TREND TOWARD CATEGORICAL POPS. CAPE AND INSTABILITY
APPEARS RATHER WEAK...SO SVR NOT EXPECTED BUT AN ISOLATED RUMBLE
OF THUNDER CANNOT BE RULED OUT. WILL TREND TEMPS BELOW MAVMOS
GIVEN EXPECTED CLOUDS AND RAIN.

GFS AND NAM DEPICT BROAD UPPER TROUGHING IN PLACE ACROSS THE UPPER
MIDWEST AND GREAT LAKES ON SUNDAY NIGHT THROUGH MONDAY. SEVERAL
EMBEDDED SHORT WAVES LOOK TOO PUSH ACROSS THE STATE WITH CYCLONIC
FLOW IN PLACE WITH DECENT LOWER LEVEL MOISTURE REMAINING AND
REACHABLE CONVECTIVE TEMPERATURES WILL TREND TOWARD CHC POPS DURING
EACH OF THESE PERIODS. GIVEN THE EXPECTED CLOUDS AND RAIN...WILL
TREND LOWS WARMER AND MONDAY HIGHS COOLER.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...

ISSUED AT 239 PM EDT FRI APR 17 2015

AN UPPER LOW SPINNING OVER ONTARIO AND SLOWLY MOVING EAST TO QUEBEC
DURING THE PERIOD WILL BRING A COOLER PATTERN INTO PLACE OVER
CENTRAL INDIANA. SOME SMALL OFF AND ON SHOWER CHANCES ARE SHOWING
UP IN THE INITIALIZATION WITH SMALL SHORTWAVES MOVING THROUGH THE
UPPER LOW. THERE/S QUITE A BIT OF SPREAD IN THE ENSEMBLES ON THE
TIMING OF INDIVIDUAL SHORTWAVES...SO THINK BEST COURSE OF ACTION IS
TO ACCEPT SUPERBLEND LOW POPS FROM WEDNESDAY ON.

&&

.AVIATION /DISCUSSION FOR THE 180300Z KIND TAF UPDATE/...
ISSUED AT 1019 PM EDT FRI APR 17 2015

NO CHANGES MADE TO THE FORECAST AT THIS TIME. PREVIOUS DISCUSSION
FOLLOWS.

AIR MASS HAS HAD A CHANCE TO DRY OUT TODAY. AS A RESULT...APPEARS
CROSSOVER TEMPERATURES WON/T BE APPROACHED UNTIL TOWARDS DAYBREAK ON
SATURDAY. FOR THIS REASON...WILL KEEP VISIBILITY RESTRICTIONS ABOVE
IFR FOR NOW...AND GO WITH MVFR RESTRICTIONS AFTER ABOUT 180800Z.

OTHERWISE...NO SIGNIFICANT CLOUD COVER...SURFACE WINDS BELOW 7 KTS
EXPECTED AT THE TAF SITES TONIGHT.

&&

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

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA/MK
SHORT TERM...PUMA
LONG TERM....CP
AVIATION...JAS

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