Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Tue Jun 18 2024

Valid 12Z Tue Jun 18 2024 - 12Z Thu Jun 20 2024

...Significant heavy rain/flash flooding threat with gusty winds well
ahead of Potential T.C. One expected to impact southern Texas on
Wednesday...

...More rounds of heavy rain and severe thunderstorms expected for the
northern Plains and upper Midwest today before shifting south into the
central Plains on Wednesday...

...A heat wave will persist over the Great Lakes, Ohio Valley and the
Northeast through midweek...

...Late-season wet snow continues across the high-elevations of the
northern Rockies today before tapering off early on Wednesday...

An active weather pattern continues across U.S. mainland.  This weather
pattern that features snow, heat, heavy rain, severe thunderstorms, strong
winds, and fire weather is now bringing Potential Tropical Cyclone One in
the midst.  A low pressure system currently intensifying along a frontal
boundary is fostering another round of heavy rain and severe thunderstorms
across the northern Plains into the upper Midwest early this morning.  The
potent upper trough and the associated dome of cold air have continued to
result in a round of late-season wet snow across the higher-elevations of
the northern Rockies together with rather strong wind gusts.  With less
potent jet stream energy behind this system, the low pressure system will
quickly eject into southern Canada by this evening, bringing the inclement
weather across the northern Plains to an end by Wednesday morning. 
However, a sharp front trailing south and southwest from the low center
will likely trigger an axis of heavy rain and severe thunderstorms from
the central Plains to the upper Midwest by tonight into Wednesday morning.
 From Wednesday into Thursday morning, the rain/storms should gradually
become more scattered in nature across the central Plains as a cool high
pressure system passes to the north.  This high pressure system will also
push the widely scattered showers and embedded thunderstorms farther east
into the lower Great Lakes and interior New England through Thursday
morning.

In stark contrast to the cool, windy, rainy and even snowy weather in the
West, a heat wave will settle and persist across the Great Lakes, Ohio
Valley and the Northeast through the next few days.  Forecast highs today
and Wednesday will reach into the mid- to upper 90s, even the century mark
Wednesday and Thursday afternoon at the hottest locations in interior
northern New England.  Widespread, numerous record-tying/breaking high
temperatures are possible.  Additionally, morning lows will remain in
about the mid-70s, at record-tying/breaking levels, providing little
relief from the heat overnight.  The early arrival of this magnitude of
heat, the duration, abundant sunshine, and lack of relief overnight will
increase the danger of this heatwave beyond what the exact temperature
values would suggest.  This is especially true for those without adequate
air conditioning, which becomes more of a concern for locations further
north that are not as accustomed to periods of persistent, intense heat.

Another big weather story over the next couple of days will be in the Gulf
of Mexico where the National Hurricane Center has already initiated
advisories on Potential Tropical Cyclone One.  Meanwhile, an elongated
upper trough digging into the southern Plains and northeastern Mexico has
already drawn a plume of tropical moisture northward into the central Gulf
Coast region.  This upper trough will be instrumental in drawing the
tropical moisture well north of the center of PTC One into southern Texas
mainly on Wednesday as PTC One tracks west toward northern Mexico.  An
axis of very heavy rain may develop just inland of the Texas coastline
behind a coastal front with dynamic support from the elongated upper
trough.  This pattern could result in locally heavy rainfall in excess of
10 inches near or just inland of the lower to upper Texas coast which
would result in significant flash flooding.  The heavy rain is forecast to
push farther inland across the Rio Grande Valley early on Thursday.  In
addition to the heavy rainfall, some coastal flooding along with tropical
storm winds can be expected up the Texas coast on Wednesday.  See the
latest advisory from the National Hurricane Center for additional detailed
updates.  Meanwhile, fire danger across the Four Corners region should
gradually ease over the next few days with the arrival of cooler air and
the arrival of moisture from the northern edge of Potential Tropical
Cyclone One.


Kong/Putnam


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php