May 16, 2019 0600 UTC Day 1 Convective Outlook
Updated: Thu May 16 06:05:37 UTC 2019 (20190516 1200Z Day 1 shapefile | 20190516 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190516 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 146,576 24,320,881 Chicago, IL...Indianapolis, IN...Milwaukee, WI...Cincinnati, OH...Fort Wayne, IN...
MARGINAL 372,185 27,713,573 Detroit, MI...Columbus, OH...Cleveland, OH...Pittsburgh, PA...Toledo, OH...
Probabilistic Tornado Graphic
20190516 1200 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20190516 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 146,852 24,436,403 Chicago, IL...Indianapolis, IN...Milwaukee, WI...Cincinnati, OH...Fort Wayne, IN...
5 % 372,034 27,540,090 Detroit, MI...Columbus, OH...Cleveland, OH...Pittsburgh, PA...Toledo, OH...
Probabilistic Large Hail Graphic
20190516 1200 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 146,576 24,320,881 Chicago, IL...Indianapolis, IN...Milwaukee, WI...Cincinnati, OH...Fort Wayne, IN...
5 % 324,784 25,028,478 Detroit, MI...Columbus, OH...Cleveland, OH...Pittsburgh, PA...Toledo, OH...
   SPC AC 160605

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0105 AM CDT Thu May 16 2019

   Valid 161200Z - 171200Z


   Severe storms are possible today and tonight from the central High
   Plains eastward into the Midwest region. Isolated strong to severe
   storms are also possible from southern Montana through northern
   Idaho during the afternoon, across portions of Utah and vicinity,
   and across parts of southeast New Mexico and West Texas.

   While a couple of upper cyclones over the eastern half of Canada
   will maintain a belt of west-northwesterly flow from the northern
   Plains across the Great Lakes and Midwest, a more amplified flow
   field is progged over the western half of the country.  This will
   manifest as a result of a trough moving inland from the eastern
   Pacific early in the period, impinging upon stout upper ridging
   centered over the High Plains.  As this system moves inland and
   acquires negative tilt with time, widespread convection -- peaking
   during the afternoon and evening -- is progged.  

   Elsewhere, a cold front is forecast to move eastward across the
   Great Lakes region, with trailing portions of this front to become
   oriented in an increasingly west-to-east manner across the mid
   Missouri Valley and Upper Midwest regions through the afternoon and
   evening.  This front should focus scattered to isolated storm
   development during the afternoon, which should then continue through
   the evening hours.

   ...Central High Plains region eastward across the mid Missouri
   Valley into the Midwest...
   Several episodes of convection are forecast within the west-to-east
   slight risk area -- beginning with a band of frontal convection
   which should be crossing the Wisconsin/Iowa area early in the
   period.  As the remnant convection -- and associated cold front --
   move into the Midwest during the afternoon, isolated to scattered
   storms should re-intensify/redevelop, as the airmass becomes
   moderately unstable.  With a belt of moderate westerly/northwesterly
   flow across this area, storms should move quickly east-southeastward
   -- accompanied by the potential for damaging wind gusts along with
   large hail.  Storms should spread southeastward through the evening,
   possibly reaching the central Appalachians late.

   Meanwhile farther west, isolated storms should develop over the
   western Nebraska/eastern Wyoming vicinity, in an upslope regime just
   north of the surface front.  While mid-level flow -- within the axis
   of the ridge -- should prove to be a bit weak, veering flow with
   height should provide sufficient shear for a few strong/locally
   severe storms, and attendant risk for hail and locally damaging
   winds.  Storms should move eastward off the higher terrain during
   the evening, with an increase in convection expected near and north
   of the surface front as south-southwesterly low-level jet develops
   overnight.  Primary severe risk would likely be large hail, given
   the slightly elevated nature of the overnight storms.

   ...Parts of northern Idaho across southern Montana...
   Large-scale ascent ahead of the upper trough -- focused at the
   surface near a baroclinic zone progged to reside from northern Idaho
   southeastward across Wyoming -- should support afternoon
   thunderstorm development.  The convection will be aided by afternoon
   heating of a modestly moist boundary layer maintained by easterly
   flow just north of the front, thus yielding weak but sufficient
   mixed-layer CAPE.  With moderately strong mid-level southerly flow
   atop the region, shear will be sufficient for organized storms --
   particularly just to the cool side of the front where the low-level
   easterlies enhance directional shear.  Though the modest CAPE should
   limit the number of stronger cells, and thus overall severe risk,
   locally damaging winds and perhaps a couple of marginally severe
   hail events are expected.  Though storms will likely continue across
   the region into the overnight hours, convection should diminish
   below severe levels during the evening.

   ...Utah and vicinity...
   Strong large-scale ascent ahead of the advancing upper trough will
   support fairly widespread convective development, as weak
   destabilization occurs in conjunction with afternoon heating.  As
   relatively strong/increasing flow with height spreads eastward
   across the area, shear supportive of fast-moving, organized storms
   will be present.  As such, risk for a few strong/damaging wind gusts
   will exist -- primarily during the afternoon and into the evening.

   ...Southeastern New Mexico into parts of West Texas...
   Southeast low-level flow on the western fringe of a southeastern
   U.S. high will maintain a feed of low-level moisture across the
   Transpecos region of Texas into southeast New Mexico.  As diurnal
   heating maximizes in the late afternoon, resulting CAPE development
   should support initiation of a few storms -- likely initially over
   the higher terrain of southeastern New Mexico/West Texas.  Though
   the magnitude of flow aloft will remain rather modest, veering of
   the flow with height may provide sufficient shear for some updraft
   rotation, and thus accompanying risk for large hail and/or damaging
   wind gusts with a couple of the stronger cells, before convection
   dissipates during the evening.

   ..Goss/Leitman.. 05/16/2019