Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 230730
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
330 AM EDT WED APR 23 2014

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

&&

.SYNOPSIS...
ISSUED AT 351 PM EDT TUE APR 22 2014

HIGH PRESSURE WILL KEEP DRY WEATHER IN THE FORECAST INTO
THURSDAY...BUT THE MOSTLY CLEAR SKIES AND FAIRLY LIGHT WINDS COULD
LEAD TO FROST TONIGHT. THURSDAY EVENING A COLD FRONT WILL APPROACH
FROM THE WEST AND BRING RAIN AND CHANCES FOR THUNDERSTORMS TO THE
AREA ESPECIALLY DURING THURSDAY NIGHT. MOSTLY DRY WEATHER IS
EXPECTED FRIDAY THROUGH SATURDAY...BUT BY SATURDAY NIGHT AN UPPER
LOW REACHING THE PLAINS AND SLOWLY MOVING EASTWARD WILL BRING
CHANCES FOR RAIN AND A FEW THUNDERSTORMS ON AND OFF TO THE AREA
THROUGH THE REST OF THE PERIOD AS WELL AS BELOW NORMAL HIGHS.

&&

.NEAR TERM /REST OF TONIGHT/...

ISSUED AT 943 PM EDT TUE APR 22 2014

CURRENT FORECAST LOOKS GOOD. WINDS STILL LOOK TO REMAIN HIGH ENOUGH
FOR LONG ENOUGH TONIGHT TO PREVENT WIDESPREAD FROST IN THE COLDEST
AREAS. WILL CONTINUE TO MENTION PATCHY FROST MOST AREAS WITH AREAS
OF FROST IN THE FAR NORTH. SHELTERED AREAS WILL HAVE THE BEST
CHANCES FOR FROST.

OTHERWISE ONLY MADE MINOR TWEAKS TO FORECAST ELEMENTS.

PREVIOUS DISCUSSION FOLLOWS...
FORECAST FOCUS IS ON TEMPERATURES AND POTENTIAL FOR FROST FORMATION.
HIGH PRESSURE CONTINUES TO BUILD OVER THE AREA WITH THE CENTER OF
THE SURFACE HIGH OVER MINNESOTA. THE CENTER OF THE HIGH WILL REMAIN
TO THE NORTHWEST OF THE AREA THROUGH THE NIGHT...KEEPING THE
PRESSURE GRADIENT ACROSS THE AREA FROM COMPLETELY SLACKENING AND
THUS KEEPING THE WINDS FROM DROPPING TO CALM. COULD SEE SOME WISPY
CIRRUS OVERTOPPING THE UPPER RIDGE AXIS BUT THIS SHOULD NOT
SERIOUSLY INHIBIT COOLING. WITH THE WIND THOUGH WENT WITH THE WARMER
MAV NUMBERS IN THE LOW 30S IN THE NORTH TO AROUND 40 IN THE
SOUTHWEST. COULD SEE SOME PATCHY FROST AND EVEN PERHAPS AREAS OF
FROST IN THE FAR NORTHERN COUNTIES BUT THE EXTENT OF THE FROST WILL
DEPEND GREATLY ON THE WINDS. THUS WITH LOW CONFIDENCE IN WIDESPREAD
FROST AND AFTER COORDINATION WITH SURROUNDING OFFICES WILL ISSUE AN
SPS FOR MOST OF THE FORECAST AREA FOR FROST BUT WILL NOT GO WITH ANY
HEADLINE.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...

ISSUED AT 351 PM EDT TUE APR 22 2014

FORECAST FOCUS IS ON POPS/TIMING OF THURSDAY/THURSDAY NIGHT SYSTEM.
MODELS ARE IN GOOD AGREEMENT AND GENERALLY USED A MOS CONSENSUS.
QUIET WEATHER WILL BE IN PLACE FOR WEDNESDAY AND WEDNESDAY NIGHT
UNDER STRONG UPPER RIDGING. WHILE MODELS ARE TRYING TO DEVELOP SOME
MINOR QPF ALONG A BUILDING WARM FRONT WEDNESDAY NIGHT OVER THE TOP
OF THE UPPER RIDGE...AT THIS TIME THINK THE RIDGE WILL BE TOO STRONG
TO ALLOW ANY RAIN TO MOVE THIS FAR SOUTH. THURSDAY MODELS ARE IN
GOOD AGREEMENT IN KEEPING THE AREA DRY THROUGH 18Z. THIS SET OF RUNS
IS A LITTLE SLOWER WITH THE PROGRESSION OF THE COLD FRONT AND THUS
LOWERED POPS TO DRY IN THE EAST AND KEPT JUST CHANCE GOING IN THE
WEST UNTIL AFTER 0Z. GOOD AGREEMENT ON A LOW LEVEL JET ENHANCING
UPWARD MOTION AHEAD OF THE FRONT BETWEEN 0 AND 6Z FRIDAY AND
MAXIMIZED POPS AT HIGH LIKELIES THEN. WITH WEAK INSTABILITY BUT
STRONG FORCING INCLUDED A CHANCE FOR THUNDER UNTIL 6Z. STILL IN THE
DAY 3 SEE TEXT...AND WITH THE TIMING OF THE FRONTAL PASSAGE AT THIS
TIME AND VERY LITTLE INSTABILITY AVAILABLE NOT ANTICIPATING A SLIGHT
RISK UNLESS NEW RUNS CHANGE THE TIMING. AFTER THAT ALL INSTABILITY
WAS GONE AND THE FRONT WAS JUST ABOUT EAST OF THE AREA. DRY WEATHER
BUILDS BACK IN FOR FRIDAY.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 330 AM EDT WED APR 23 2014

HIGHLY AMPLIFIED BLOCKY PATTERN DEVELOPING ALOFT WITH THE KEY PLAYER
IN WEATHER THROUGHOUT THE EXTENDED BEING AN UPPER LOW WHICH WILL
DEEPEN AS IT MOVES INTO THE CENTRAL PLAINS LATE WEEKEND...BECOME
CUTOFF FROM THE MEAN FLOW...THEN MEANDER SLOWLY EAST INTO THE
EASTERN U S BY THE MIDDLE OF NEXT WEEK. THIS WILL RESULT IN AN
EXTENDED PERIOD OF UNSETTLED WEATHER ACROSS THE REGION BEGINNING
SATURDAY NIGHT AND CONTINUING THROUGH THE END OF THE EXTENDED...AND
LIKELY BEYOND.

THE PRESENCE OF THE UPPER LOW OVER THE HIGH PLAINS ON SUNDAY WILL
PROMOTE SURFACE CYCLOGENESIS IN THE CENTRAL ROCKIES...WITH THE
SURFACE WAVE EJECTING INTO WESTERN KANSAS LATE SUNDAY AND DEEPENING
AS IT DOES SO. A WARM FRONT WILL EXTEND EAST FROM THE SURFACE WAVE
INTO THE REGION WITH SCATTERED CONVECTION BECOMING INCREASING LIKELY
DURING THE SECOND HALF OF THE WEEKEND AND INTO EARLY NEXT WEEK.
WHILE 00Z MODEL GUIDANCE IN RELATIVELY GOOD AGREEMENT ON THE
LOCATION OF THE UPPER LOW AND SURFACE WAVE...THERE REMAIN
DIFFERENCES ON WHERE THE WARM FRONT EVENTUALLY SETS UP. THE ECMWF
REMAINS FURTHEST NORTH...SIMILAR TO ITS 22/12Z RUN...AND PLACES MUCH
OF THE FORECAST AREA WITHIN THE WARM SECTOR. OP GFS AND GGEM REMAIN
SOUTH CLOSER TO THE OHIO RIVER. HAVE BUMPED UP TEMPS A FEW DEGREES
FROM PREVIOUS FORECAST FOR SUNDAY THROUGH TUESDAY BUT SHOULD THE
MORE NORTHERN PLACEMENT TO THE BOUNDARY VIA THE ECMWF SOLUTION BE
REALIZED...TEMPS WILL NEED TO BE RAISED FURTHER. WILL CONTINUE TO
MONITOR.

REGARDLESS OF THE EXACT PLACEMENT OF THE FRONT...HIGH CHANCE POPS
ARE WARRANTED FROM SUNDAY THROUGH THE MIDDLE PART OF NEXT WEEK AS
THE SURFACE WAVE DRIFTS EAST INTO THE OHIO VALLEY BY THE END OF THE
PERIOD. SIGNS CONTINUE TO POINT TO THE UPPER LOW CARVING OUT A BROAD
TROUGH OVER THE EASTERN HALF OF THE COUNTRY...RESULTING IN AN
EXTENDED PERIOD OF COOL DAMP WEATHER POSSIBLY IMPACTING CENTRAL
INDIANA THROUGH THE END OF NEXT WEEK.

&&

.AVIATION /DISCUSSION FOR THE 230600Z TAFS/...

ISSUED AT 1103 PM EDT TUE APR 22 2014

VFR CONDITIONS ARE EXPECTED TO CONTINUE.

HIGH PRESSURE OVER THE WESTERN GREAT LAKES AND UPPER MIDWEST WILL
CONTINUE TO SLOWLY BUILD EAST ACROSS THE GREAT LAKES AND OHIO
VALLEY DURING THIS PERIOD. TIME HEIGHT SECTIONS AND FORECAST
SOUNDINGS REMAIN VERY DRY...AMID SUBSIDENCE ASSOCIATED WITH THE
PASSING HIGH PRESSURE SYSTEM.

HIGH CLOUDS ARE EXPECTED TO INCREASE AFTER 00Z THURSDAY AS A WARM
FRONT APPROACHES FROM THE WEST. DRY AIR IN PLACE AT THE LOWER
LEVELS WILL CONTINUE TO PROVIDE VFR CONDITIONS.

&&

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

&&

$$

SYNOPSIS...CP
NEAR TERM...CP/50
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...JP

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