Highs in the lower 50s throughout the day. Tomorrow doesn't look better. This weekend's system is only the beginning. Models are hinting an blocking pattern developing soon. Already, another wet weekend is set to be on tap, potentially worse that this weekend. For instance, Thursday morning from the 18z GFS run:
ILN:
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
A vertically-stacked cutoff low will continue to spin
north/northeast of the Ohio Valley Tuesday through Thursday
while the system slowly drifts towards the northeastern US. As
this occurs, surface high pressure will simultaneously try to
build into the Ohio Valley from the west despite the area being
on the southwestern flank of the upper-level low and possibly
the far western flank of the surface low. This messy synoptic
setup leaves the region in a regime with northwesterly/northerly
surface winds through the middle of the work week along with
sporadic chances for light rain showers and increased cloud
cover when occasional, low- predictability, vorticity maximums
rotate around the upper-level low. Northwesterly winds help keep
temperatures near seasonal norms for the middle of April
through Thursday.
By Friday,the upper-level cutoff low reaches the northeast
coast. This will likely result in the surface low translating to
the eastern seaboard in a region more favorable for
cyclogenesis. With the upper-level low and newly formed surface
low off the east coast, upper level ridging may briefly build in
over the Ohio Vally on Friday despite northerly surface winds
persisting along with seasonal temperatures and dry conditions.
Rain chances then increase for the weekend due to upper-level
ridging breaking down and the possibility of an upper-level
shortwave approaching.
&&
IND:
&&
.Long Term...(Tuesday through Sunday)
Issued at 244 PM EDT Sun Apr 11 2021
A blocky and stagnant flow aloft will develop through the
week...anchored by two upper level low pressure systems. The first
will track slowly east across the Upper Midwest and Great Lakes
Tuesday and Wednesday before slowly drifting into New England and
the Canadian Maritimes by the weekend. The second lobe will develop
over the Intermountain West midweek then gradually shift east
towards the region by the weekend in a weakened state. Quasizonal
flow will persist south of the track of these two lobes through the
Ohio Valley for much of the upcoming week.
The presence of a weakening surface wave over the Great Lakes in
tandem with the upper level low on Tuesday and Wednesday will bring
a brief shot of cooler air drawn into thew region with additional
cloud cover. Forcing associated with this system will remain north
of the region however with a separate surface wave tracking through
the lower Tennessee Valley and keeping much of the Ohio Valley in
between with drier air advecting in from the Canadian prairies. As
the work week progresses...broad high pressure will only strengthen
across the region with dry weather continuing.
The approach of the weakening western upper low by the weekend will
introduce some potential for rain showers but a poorly defined
surface low and disruption to any substantial low level flow
developing off the Gulf of Mexico suggest a problematic setup for
more expansive rainfall over the forecast area. At this point...hard
to justify much more than 20-30 pops for scattered showers and an
increase in cloud cover as the upper wave drifts through the area.
The strong high pressure ridge building south from Canada will keep
a seasonably cool airmass across the Ohio Valley through the
extended with highs largely ranging from the mid 50s to the lower
60s. Lows at night will dip into the upper 30s and lower 40s with
at least some potential for patchy frost in parts of the forecast
area Wednesday and Thursday nights then again by early next week.
&&