- Day Three
acus03 kwns 060730
Storm Prediction Center ac 060729
Day 3 convective outlook
National Weather Service Storm Prediction Center Norman OK
0229 am CDT Monday Jul 06 2015
Valid 081200z - 091200z
..there is a marginal risk of severe thunderstorms Wednesday afternoon and evening
across parts of the middle Mississippi Valley...
Thunderstorms capable of producing a few potentially damaging wind
gusts or...perhaps...an isolated tornado or two may not be out of
the question on Wednesday across portions of the middle Mississippi
Valley. Otherwise...severe weather potential across much of the
nation appears generally negligible.
Seasonably high moisture content air is generally forecast to remain
confined to areas along and south of a surface frontal zone
advancing to the southeast of the stronger middle-latitude westerlies
..which will remain near and north of the Canadian/U.S. Border
through this forecast period. While the front may advance off
northern Atlantic coastal areas...it is expected to remain
quasi-stationary while weakening across the Ohio Valley into the
Modest middle-level subtropical ridging is forecast to continue
expanding westward across the Gulf Coast region...with flow
transitioning to broadly anticyclonic on its periphery...from
portions of the southern/Central Plains through the Ohio Valley and
middle/North Atlantic coast. However...at least one convectively
generated or enhanced perturbation emerging from the south Central
Plains appears likely to be embedded within this regime...and may
remain fairly well-defined while crossing the middle Mississippi
Valley...before becoming increasingly sheared to the east northeast.
Farther west...a significant middle/upper closed low...associated with
a weak southern branch of middle-latitude westerlies and the
subtropical jet...may begin slowly developing inland across the
..middle Mississippi Valley...
The potential strength of the convectively generated or enhanced
perturbation emerging from the south Central Plains remains unclear.
However...the flow field accompanying it may be strong and sheared
enough to enhance convective potential along the remnant frontal
zone. The best chance for this seems to exist across parts of east
central Missouri and central/southern Illinois...into adjacent areas
of Indiana...during the peak afternoon heating of a moist boundary
layer characterized by 70f+ surface dew points. One or two storms
with supercell structures capable of producing relative brief/weak
tornadoes may not be out of the question.