870
FXUS63 KIWX 190737
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
337 AM EDT TUE MAR 19 2019
SYNOPSIS
ISSUED AT 337 AM EDT TUE MAR 19 2019
ANOTHER QUIET DAY WITH HIGHS IN THE UPPER 40S UNDER PARTLY CLOUDY
SKIES. LIGHT RAIN IS EXPECTED ON WEDNESDAY BUT DRY CONDITIONS RETURN
FOR THE REST OF THE WEEK WITH TEMPERATURES SLOWLY CLIMBING THROUGH
THE WEEKEND.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 337 AM EDT TUE MAR 19 2019
ANOTHER QUIET WEATHER DAY ON TAP AS CONFLUENT W/NW FLOW ALOFT
MAINTAINS GENERAL SUBSIDENCE AND SURFACE HIGH PRESSURE OVER A LARGE
SECTION OF THE EASTERN CONUS. THERE WILL STILL BE A FAIR AMOUNT
OF CLOUDS AS LOW LEVEL FLOW BACKS LATER IN THE DAY AND WARM/MOIST
AIR ADVECTION INCREASES STRATOCU POTENTIAL. SATELLITE IMAGERY ALSO
SHOWS A PLETHORA OF UPPER LEVEL CLOUDS FROM PV ANOMALY WELL
UPSTREAM AND THESE HIGHER-BASED CLOUDS WILL PASS THROUGH OUR AREA
TODAY. SOME SUN EXPECTED AT TIMES BUT ANTICIPATE PARTLY CLOUDY
SKIES FOR MUCH OF THE DAY. DESPITE THE CLOUD COVER...SLOW BUT
STEADY WAA (850MB TEMPS CLIMBING NEAR -5C) SHOULD PUSH HIGHS INTO
THE UPPER 40S BY LATE IN THE DAY. FORECAST SOUNDINGS ALSO CONSISTENT
IN SHOWING MIXING DEPTHS OF 5-6 KFT THIS AFTERNOON...AIDING DIURNAL
TEMP RISE. NEXT SYSTEM APPROACHES LATE TONIGHT AND CARRIED SOME LOW
CHANCE POPS IN THE FAR WEST BUT BULK OF THE EVENT WILL BE AFTER 12Z
WED. INCREASING CLOUDS AND SOUTHERLY WINDS WILL LEAD TO A MILDER
NIGHT WITH LOWS AT OR JUST ABOVE THE FREEZING MARK.
LONG TERM
(WEDNESDAY THROUGH MONDAY)
ISSUED AT 337 AM EDT TUE MAR 19 2019
A FAIRLY COMPLICATED PATTERN EVOLUTION FOR WED...THOUGH RESULTANT
SENSIBLE WEATHER IS NOT VERY IMPACTFUL. ROBUST SHORTWAVE CURRENTLY
DIVING THROUGH THE NORTHERN PLAINS WILL EVENTUALLY ROUND THE BASE OF
THE LONGWAVE TROUGH AND PHASE WITH SECONDARY JET STREAK/VORT MAX
DIVING DUE SOUTH OUT OF NUNAVUT AND INTO THE GREAT LAKES. NET RESULT
IS A FAIRLY HEALTHY LOCAL INCREASE OF 285-290K ISENTROPIC ASCENT
WED. GRADIENT TIGHTENING AHEAD OF CONVERGENT BOUNDARY YIELDS 50 KT
LLJ ORIENTED PERPENDICULAR TO (SOMEWHAT) TIGHTLY PACKED ISOBARS.
THIS ALSO PUSHES MIXING RATIOS NEAR 4 G/KG IN THAT LAYER. SOUNDINGS
SUGGEST NOT QUITE ENOUGH LOW LEVEL MOISTURE ADVECTION TO GENERATE
ANY ELEVATED CAPE/THUNDER BUT STABILITY IS CERTAINLY REDUCED. THIS
WILL SUPPORT A WIDESPREAD LIGHT RAIN EVENT WED. OUTSIDE CHANCE OF A
FEW SNOWFLAKES AT THE VERY ONSET BUT HARDLY EVEN WORTH MENTIONING AS
WAA AND DIURNAL CLIMB QUICKLY PUSH SURFACE WET BULB TEMPS WELL ABOVE
FREEZING. BULK OF OUR PRECIP WILL BE DRIVEN BY ISENTROPIC ASCENT/
THETA-E ADVECTION BUT CHANCE FOR SCT SHOWERS WILL CONTINUE INTO WED
NIGHT WITH PASSAGE OF STRONG MIDLEVEL VORT MAX AND ASSOCIATED COLD
FRONT. ONCE AGAIN A VERY LOW CHANCE OF A FEW WET SNOWFLAKES WITH WED
NIGHT SHOWERS BUT CERTAINLY NO ACCUMULATION OR IMPACTS.
THU-SAT PERIOD STILL LOOKING QUIET. FLOW BECOMES ALMOST DUE
NORTHERLY DURING THE PERIOD AND WILL MAINTAIN COOL CONDITIONS. SOME
POTENTIAL FOR PRECIP THU NIGHT WITH ANOTHER WAVE DIVING SOUTH
THROUGH THE GREAT LAKES BUT CURRENT TRACK (AS SUGGESTED BY 00Z
DETERMINISTIC SUITE) WOULD KEEP BEST CVA TO OUR NE. WILL CONTINUE
WITH DRY FORECAST BUT KEEP AN EYE OUT FOR POSSIBLE TRACK SHIFTS.
SOUTHWEST FLOW RETURNS SUN WITH A BRIEF WARMUP AND RAIN CHANCES INTO
MONDAY. HOWEVER...LATEST GUIDANCE NOW SUGGESTS A QUICK EXIT OF
REMNANT UPPER LOW TO OUR SOUTH WITH STRONG HIGH PRESSURE BUILDING
OVER THE GREAT LAKES. THIS WOULD YIELD A RETURN TO DRY (AND COOL)
CONDITIONS BY TUE/WED OF NEXT WEEK.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 133 AM EDT TUE MAR 19 2019
A QUIET AVIATION WEATHER PERIOD WILL BE IN STORE FOR THE NEXT 24
HOURS. AN EXITING WEAK SHORT WAVE ACROSS NORTHWEST OHIO SHOULD
KEEP MOST OF VFR LOW CLOUDS EAST OF TERMINALS OVERNIGHT, WITH
MAINLY JUST CIRRUS OVERSPREADING TERMINALS THROUGH DAYBREAK. VERY
LOW END PROBABILITY MAY EXIST FOR PATCHY SHALLOW FOG THIS MORNING,
BUT WILL CONTINUE TO OMIT FROM FORECAST DUE TO LOW CONFIDENCE.
SCT-BKN DIURNAL VFR CU IS EXPECTED TO DEVELOP AGAIN THIS
AFTERNOON. STRONGER SHORT WAVE IS EXPECTED TO BRING SOME LIGHT
RAIN SHOWERS BACK TO NORTHERN INDIANA WELL AFTER THIS FORECAST
VALID PERIOD BY WEDNESDAY MORNING. WINDS TO REMAIN LIGHT THROUGH
THIS PERIOD, WITH SOUTHWEST WINDS OF AROUND 10 KNOTS THIS
AFTERNOON DURING PEAK MIXING.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...MARSILI
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