Area forecast discussion
National Weather Service quadrant cities Iowa Illinois
713 PM CDT Monday Jun 17 2013
Synopsis...
issued at 345 PM CDT Monday Jun 17 2013
A stalled frontal boundary was located across our far southern County Warning Area
with precipitable waters of 1.0 to 1.50 inches south of the boundary.
There was also an 850 mb frontal boundary farther south in central MO.
The bulk of the thunderstorms are occurring along that boundary
and where the highest precipitable waters were located. Other scattered thunderstorms
were along a slow moving cold front that stretched from northern
Minnesota to central WI and into Southern Lower Michigan. Temperatures were in
the 80s across the dvn County Warning Area.
&&
Short term...(this evening through tuesday)
issued at 345 PM CDT Monday Jun 17 2013
Forecast focus on small chances for thunderstorms.
Tonight...not much support for thunderstorms but will maintain
slight chances early this evening for isolated convection until
sunset and loss of heating. Moisture is limited...boundaries are
well south and north of the dvn County Warning Area but there is a weak short wave
arriving out of South Dakota. Minimum temperatures will range from the middle
50s north to lower 60s south.
Tuesday...will have 20 to 30 percent probability of precipitation as a decent short wave
drops into the County Warning Area which is currently in ND. A weakening back door
cold front will also be pushing into the County Warning Area. However...low level
forcing is weak...moisture/instability is rather limited and lapse
rates become more stable with time. Moreover...weak Theta-E
gradient diminishes during the day. Northeast winds will keep
afternoon temperatures several degrees below normal...ranging from
the middle to upper 70s north to lower 80s south.
Long term...(tuesday night through monday)
issued at 345 PM CDT Monday Jun 17 2013
Overall not much change to long term forecast. Relatively quiet/dry
to start out the period as high pressure builds into the region from
the Great Lakes...with cool early Wednesday morning low temperatures in
the lower and middle 50s in northeast half of County Warning Area. A few isolated
upper 40s readings possible in parts of northwest Illinois.
A gradual warming trend commences Wednesday...lasting into the weekend.
A return to a more active period of shower and thunderstorm
chances...albeit lower end...begin Thursday through early next week.
With Summer starting on Friday...right on cue the heat and humidity
will be in place with dewpoints in the upper 60s to middle 70s and
heat indexes in the 90s to lower 100s. Any thunderstorms that do
develop will likely be heavy rain producing. Upper level ridging
is in place through the extended...with the County Warning Area on the northern
periphery. Will be difficult to determine this far out exact
placement and timing of any waves that ride the ridge resulting it
shower/thunderstorm activity across the area versus dry conditions.
&&
Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 704 PM CDT Monday Jun 17 2013
Isolated showers or thunderstorms will dissipate by 03z. Otherwise
VFR conditions will continue over the area through Tuesday
afternoon. A cold front will move in from the northeast overnight
switching winds to the northeast. Isolated showers and
thunderstorms are possible again mainly during the afternoon. The
chance of a shower or thunderstorm at any one point will be low, so
no mention in the tafs at this time.
Dlf
&&
Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&
$$
Synopsis...haase
short term...haase
long term...Philip
aviation...dlf
