Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Mon Sep 16 2024

Valid 00Z Tue Sep 17 2024 - 00Z Thu Sep 19 2024

...Potential Tropical Cyclone Eight expected to make landfall and bring
gusty winds, heavy rain, and embedded strong thunderstorms up the
Carolinas into portions of the Mid-Atlantic...

...A strong upper low will bring unsettled weather and well below normal
temperatures to the West with high elevation wet snow for the Sierra
Nevada and northern Rockies...

...Severe thunderstorms possible for the northern and central High Plains
Tuesday into early Wednesday...

As a persistent ridge of high pressure continues to provide fine fall-like
weather for the northeastern quadrant of the country, Potential Tropical
Cyclone Eight (PTC8) is making landfall near the North/South Carolina
border.  Although PTC8 was able to acquire some tropical characteristics
over the warm waters of the Gulf Stream, the cool air mass that the high
pressure system has been feeding into the circulation of PTC8 has kept it
from becoming fully tropical.  Nevertheless, tropical moisture has
continued to overrun the coastal frontal boundaries and precipitate as
heavy rain with embedded strong thunderstorms especially over the coastal
plain of North Carolina just north of where PTC8 makes landfall.  A few
tornadoes cannot  be ruled on either across eastern North Carolina through
this evening.  Flash flooding will be a concern, especially in the eastern
Carolinas where the highest rainfall totals are forecast for tonight. 
PTC8 is forecast to move slowly inland near the North/South Carolina
border and steadily weaken as a swath of heavy rain overspreads mainly
across North Carolina into portion of South Carolina through much of
Tuesday.  The remnants of PTC8 will then spread northward into the
Mid-Atlantic later Tuesday and into Wednesday bringing a threat of
flooding rains but the intensity of the rain is forecast to gradually
decrease with time.

In the West, a deep upper low will bring unsettled weather and well below
normal temperatures to the region this week. The upper low is accompanied
by a strong surface frontal system that will push east across the
Intermountain West through tonight and into the Plains Tuesday afternoon.
This system will bring widespread precipitation chances and gusty winds to
much of the West. Precipitation will fall mainly in the form of showers
and thunderstorms, but temperatures will be cold enough for portions of
the high elevations of the Sierra Nevada and the northern to see some
early-season wet snow. Winter Weather Advisories are in effect through
this evening for the Sierra Nevada above 8000 feet where up to 4 inches of
snow may fall, and Wind Advisories are in effect into this evening for
portions of the Southwest where wind gusts could exceed 45 mph.

A surface low pressure system is forecast to strengthen in the lee of the
Rockies over Wyoming and Montana, and will bring a threat of scattered
severe thunderstorms to the northern and central High Plains Tuesday
afternoon and into early on Wednesday. The Storm Prediction Center has
highlighted these areas with a Slight Risk of Severe Thunderstorms (level
2/5), and the main storm hazards will be severe wind gusts and hail.
Showers and thunderstorms will push east across the Plains Tuesday night
and move farther east across the northern and central Plains on Wednesday
when additional strong thunderstorms are possible.

Temperatures will have a sharp contrast across the United States over the
next few days. The deep upper low will result in well below normal
temperatures in the West through at least mid-week, with the coldest
anomalies over the Great Basin and California where high temperatures will
be as low as 15-25 degrees below normal. On the flip side, temperatures
will be well above normal in the Central U.S. and Northeast. High
temperatures will generally be in the 80s and 90s for these regions. Below
normal temperatures are also forecast for the Southeast and Mid-Atlantic
today and Tuesday due to expected precipitation and cloud cover, but
temperatures should return to near normal for these regions by Wednesday.


Kong/Dolan


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