Scientific Forecaster Discussion
Area forecast discussion
National Weather Service northern Indiana
720 PM EDT sun Apr 26 2015
issued at 550 PM EDT sun Apr 26 2015
High pressure will be over the region into Monday. This will provide
dry weather and partly cloudy skies. Low temperatures tonight will
range from the middle 30s in southern Michigan to the upper 30s
near the Ohio River. High temperatures on Monday will range from
the middle 50s in southern Michigan to the lower 60s along the
Short term...(this evening through monday)
issued at 351 PM EDT sun Apr 26 2015
Quiet weather to continue through the short term period with main
items of interest centered on temperature/sky cover trends tonight/Monday.
Upper vorticity maximum across northern lower Michigan will continue to
rotate through parent upper circulation this evening. This short
wave will have very little in the way of any moisture to work
with...and only just an increase in afternoon cumulus has been noted
downstream of this forcing across central lower Michigan. While
coverage of this cumulus field should diminish somewhat with southward
progression into local area this evening...forcing with approaching
short wave should allow for scattered low clouds particularly across
northeast/east sections this evening. A weak to moderate gradient
should remain in place and thus confidence remains low on frost
formation overnight. Will maintain mins from middle 30s west to middle to
upper 30s east...with the possibility of slightly more cloud cover
across the east.
Looking farther upstream...a somewhat stronger upper wave is
tracking westward across northwest Quebec and should drop into
Northeast Indiana/Northern Ohio Monday morning. Slightly better
moisture profiles wrapping around upper low should accompany this
second wave...with a better chance of more solid low cloud cover
across the east/northeast. Temperature profiles appear to be fairly
similar tomorrow...although perhaps with slightly more limited
mixing. Thus...have maintained highs tomorrow from previous forecast
that are in the ballpark to that observed today. Cooler conditions
expected closer to Lake Michigan once again as onshore flow
Long term...(monday night through sunday)
issued at 351 PM EDT sun Apr 26 2015
Skies will quickly clear Monday evening...setting the stage for
strong radiational cooling as winds become light. Greatest impact
will take place in western third to half of the area where sky cover
will dissipate quicker. Have lowered lows a touch and expanded
mention of patchy frost. Frost headlines may be needed with extended
period of frost possible. Limited ridging will allow for warmer
temperatures and dry conditions into at least Tuesday night and
possibly Wednesday night. Phasing of systems still expected but may end up
more south of the region vs southeast as larger upper low slower to depart.
With the area still grossly lacking moisture...not looking promising
for showers with models now backing off Wednesday and shifting somewhat
to Wednesday night. Have kept with slight chance probability of precipitation but suspect later
forecasts will end up removing as well.
Troughy pattern will hold into Friday before upper level ridging
increases and the area finally sees a return to much warmer
temperatures. A weak disturbance will try to move across the Great
Lakes with some hints of a marginal shower chance. Have toned down
superblend and went with general slight chance for as moisture will return
but not be overly deep.
Aviation...(for the 00z tafs through 00z Monday evening)
issued at 716 PM EDT sun Apr 26 2015
Diurnal cumulus field was beginning to dissipate with loss of heating.
Lake breeze has worked well inland and also helped to clear skies.
Two short waves will rotate into the area...one later this evening
and the second Monday morning into afternoon. First wave will
bring middle level cloud deck south with kfwa on western fringe.
Still expect VFR conditions. Stronger wave still looks to be
Monday morning. This could bring some mfvr ceilings to the region but
still not ready to jump on this restriction. Will see how cloud
bases behave upstream overnight and stay optimistic with VFR for
Lm...Small Craft Advisory until 11 PM EDT this evening for lmz043-046.
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