Subtropical storm forming off East Coast but otherwise a beautiful week ahead

A cut-off low pressure system has formed off the Carolina / Mid-Atlantic coast of the United States and is slowly but surely developing convection (showers) around a broad center.

Models expect a subtropical cyclone to form — around 1000 mb minimum pressure in the next 3-days with tropical storm force winds — so NHC has hoisted a 40% chance of Subtropical Storm Josephine formation. The system is over marginal SSTs around 23° to 25°C but the upper-level (tropopause) is colder, so convection should fire readily over the center … with some warmth/moisture provided by the nearby Gulf Stream.

Main risk/threat will be gusty coastal winds and battering waves for several days out of the Northeast —> this Nor’easter may get a name!

Weather Next 3 Tracks — Next 15-days through November 2nd — running out of Atlantic hurricane season but may have some additional activity!

Chance of any subtropical or tropical cyclone off the East Coast around 60%

Note the additional 10%+ area popping up off Florida into Week 2 — again at the tail end of a frontal boundary / trough: Only looking at genesis:

The next Eastern Pacific hurricane will be named Vance.

Impacts in terms of rainfall —> might be none. Dry air pulled out of the Northeast is dry (origin Canada) so the entire western edge of potential Josephine will be sunny and cool.

Blend of Models Precipitation Next 7-days | Huge 4-Corners totals

Focus for active weather will be across the Western U.S. with a strong trough and moisture flowing out of the subtropical/tropical Pacific into the Southwest.

A solid inch of rain along the Southern California coast including Los Angeles. 1” to 2” around Phoenix and upwards of 4” in SW Colorado (no idea what cities are there)

Overall Median Precipitation next 15-days —> quite dry across the eastern half of the Lower 48

My favorite parameter — precipitable water | ECMWF 18z next 6-days

The Nor’easter is perfectly situated off the East Coast that major moisture impacts (heaviest rain) should miss land entirely.

The cut-off low swirls down the west coast to bring atmospheric river flow into California later next week. Just the beginning of a long winter of West Coast storms. Also, the remnants of Hurricane Trudy are pulled northward ahead of the cut-off low into the Southwest — and boost rainfall amounts considerably for AZ/NM/CO

Temperature Analysis earlier at 9:30 PM ET

Temperature Analysis | Anomaly from Normal

Lower 48 was -3.1°F below normal

High Temperatures next 9-Days

Moderating over the the entire week with the coldest air bottled up in Canada all week into next weekend.

This evening’s HRRR precipitable water … dry across the Eastern U.S. with northeasterly flow behind the Subtropical Storm draining into the Southeast and even Florida —> sunshine, perfect weather

Moisture builds into the Southwest ahead of arrival of former Hurricane Trudy and the cut-off low spinning off California coast.

Simulated radar into Tuesday 8 PM ET

Low Temperatures Monday Morning

3% of the Lower 48 real estate freezing | only 2 million population

High Temperatures on Monday

60s and 70s widespread across the Lower 48.

Blend of Models Snowfall Next 10-days

Snowfall Next 15-days | ECMWF Ensemble Median

Probability of 1-inch or more of snowfall into early November

Integrated Vapor Transport Next 10-days | AIFS 18z Flagship Model

Hurricane Vance forms off the coast of Mexico and drifts northward … and otherwise mostly dry easterly flow across the Gulf —> shuts down the moisture flow into the eastern U.S. —> dry and cool —> and as I said before — perfect weather for raking leaves or decorating your yard for Halloween.

Height Anomaly Next 10-days

Sequence of strong troughs dip along the West Coast of the USA

Strong ridge repeats over Great Lakes / Canada

And we have another cut-off this time off Florida — over warmer SSTs so we need to watch for a tropical storm or hurricane forming (10% chance)

Week 1 Temperature Anomaly | Oct 18 - Oct 24

Week 2 Temperature Anomaly | Oct 25 - Oct 31

Atlantic Tropical Outlook | Subtropical Storm 40%

Change of plans with NHC now showing 40% chance of subtropical development with the coastal low pressure system. Nothing really there yet.

ECMWF Ensemble 12z full-physics tracks next 15-days

Tracker picks up the looping Nor’easter off the Mid-Atlantic coast and a bunch of other tracks that emanate out of the subtropics east of Florida — so we are not done with hurricane season at all.

Google Deep Mind | Weather Next 3 | 18z Tracks (64-members)

Eastern Pacific Tropics | Hurricane Trudy

Next storm is Vance. Hurricane Trudy is about to rapidly collapse and become a remnant low.

Weather Next 3 Ensemble Cone —> Tropics Earth

Median Peak of Next System — Vance around 110 knots = Another Major

Also, some tracks around Hawaii

Western Pacific Tropics | Super Typhoon Champi

Champi should miss Taiwan to the north (barely) … intensity has fluctuated after an eyewall replacement cycle — in the mid-range Category 4 to Category 5 expected for next 3-4 days on a WNW track over warm water

Champi = beautiful and powerful Super Typhoon (even though JTWC is low with intensity)

Weather Next 3 Ensemble Cone —> Tropics Earth

Extreme intensity still expected with Champi —> 153-knots median

Global Genesis and Tracks — multiple basins all active … including Southern Indian Ocean + Bay of Bengal

Thank you for visiting / reading — always more to come!

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