Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Sun Sep 27 2026

Valid 00Z Mon Sep 28 2026 - 00Z Wed Sep 30 2026

...A round of heavy rain and embedded thunderstorms associated
with the meandering Nor'easter is forecast to impact southern New
England to the northern Mid-Atlantic through tonight and into
Monday...

...Flash flood threat emerges and expands quickly across the Four
Corners region as an upper trough interacts with tropical moisture
from Polo and Odalys...

The strong low-pressure system that has been impacting New England
and the northern Mid-Atlantic over the weekend made landfall over
central and southern New Jersey today as it gradually weakens. The
center of this Nor'easter is moving southward in a cyclonic loop,
brushing the southern coastline of New Jersey before gradually
taking an east-northeast track and passing south of Long Island
through Sunday night. As the final piece of an upper-level trough
completely merges with the system, the Nor'easter will enter its
gradual weakening stage. However, a batch of heavy rain with
embedded thunderstorms forming on the eastside of the weakening
system south of Long Island is expected to rotate toward and
across southern New England and into much of New Jersey through
tonight. The low-pressure center will not exit quickly, and
southern New England will remain under the threat of moderate to
heavy rain for much of Monday. Strong and gusty onshore wind will
buffet coastal New England from Cape Cod northward, potentially
reaching gale force Sunday night into early Monday. Light to
moderate rain will then overspread the remaining areas of northern
New England on Monday before the weakening Nor'easter finally
exits into Nova Scotia by Tuesday evening.

Outside of the Nor'easter, much less active weather is found
across the rest of the country to end this weekend. However, this
tranquil weather pattern will be short-lived as the threat of
flash flooding emerges and then quickly expands across the Four
Corners region over the next couple of days. This is in response
to an upper-level trough moving onshore into California ingesting
tropical moisture coming from the twin tropical cyclones Polo and
Odalys currently over the eastern Pacific. Monday should see the
initial expansion of showers and thunderstorms across much of the
Four Corners states ahead of the upper trough. This will be
followed by the core of the tropical moisture from Polo moving
through northern Mexico on Tuesday, reaching New Mexico later that
day. WPC is highlighting a large area of slight and moderate risk
of flash flooding engulfing much of the Four Corners states Monday
and Tuesday, with more focus toward New Mexico on Tuesday. Much of
the region can expect to receive 2 inches of rainfall with much
higher amounts likely due to localized terrain effects. There is
uncertainty regarding the track of Polo's remnants across northern
Mexico and how much of Polo's circulation remains by the time it
reaches the U.S. Please stay tuned to this emerging flash flooding
event across the Four Corners states over the next couple of days.


Kong


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