9/30-10/5 Joaquin-Trough Interaction-DISCUSSION/OBS

[Superstorm93]

[Superstorm93]

Not sure if we should make a tropical thread just yet. Give it another day to simmer on the back burner. 

 

[Superstorm93]

GFDL is also a bit hyped up. 

 

[Brian5671]

Not sure if we should make a tropical thread just yet. Give it another day to simmer on the back burner. 

 

might want to split into 2 threads, the Tue-Wed frontal rains (Which look decent) and then the 2nd deal Thur-Sun

[IsentropicLift]

The MMEFS flood model which runs off the GEFS ensembles is indicating that most of the area rivers would exceed flood stage after 5" of rain has fallen.

[IsentropicLift]

The JMA agrees

 

 

Tropical moisture

 

[Juliancolton]

This is a bit reminiscent of the heavy rains and flooding in early October 2005, stemming from the interaction of post-tropical TS Tammy and a slow-moving cold front.

[IsentropicLift]

[kevbo81]

This is a bit reminiscent of the heavy rains and flooding in early October 2005, stemming from the interaction of post-tropical TS Tammy and a slow-moving cold front.

 

i was thinking that today as well. 

[Superstorm93]

12z ECM Ens are insansely spread out with TD11 

 

Big story is that it still delivers 8-10" of rain to parts of NE 

[IsentropicLift]

12z ECM Ens are insansely spread out with TD11 

 

Big story is that it still delivers 8-10" of rain to parts of NE 

The mean is very wet and supports the OP very well. This is about as close of a lock for a prolific heavy rain event that you're going to see.

[Superstorm93]

[Ericjcrash]

12z ECM Ens are insansely spread out with TD11 

 

Big story is that it still delivers 8-10" of rain to parts of NE

I'll be in OCMD this weekend for a car show. What a disaster. Does the euro ens ensure a soaking there throughout the weekend? And seriously, October has been a wild month in the past handful of years.

[Superstorm93]

The center of the depression has been moving well to the left of
the previous track, with the initial motion estimated to be 270/05
kt. In addition to the more westward initial motion, there have
been significant changes in the model guidance, with the latest
ECMWF forecast taking the cyclone much farther south and west than
the GFS in 3-5 days. This appears to be the result of enhanced
mid-level ridging to the north of the cyclone in the ECMWF at that
time frame. This has necessitated a significant southwestward
shift of the official forecast, although for continuity the new NHC
track does not take the cyclone as far to the southwest as the
ECMWF. Given the large spread now seen in the dynamical track
guidance, confidence in the track forecast is rather low.

The strong shear over the system is likely to continue for at least
the next 12-24 hours and given the large displacement between the
low- and mid-level centers, no intensification is anticipated in
the short term. The dynamical guidance indicates some relaxation
of the shear in a day or two, so the official forecast shows the
cyclone strengthening into a tropical storm later on Tuesday. This
is close to the intensity model consensus through 48 hours, and a
little below it thereafter. Given the large uncertainty in the
track forecast, there is also uncertainty as to what kind of
environment the cyclone will encounter during the forecast period,
which also leads to low confidence in the official intensity
forecast.

 

 

[WaPo]

It seems like people are being cautious here, and rightfully so. Not all the models are completely onboard about the strengh/precip. That said, Ukie is now on board as well. If the GFS follows, we've got something to talk about. 

 

I still don't think the blocking will be strong enough. 

[PB GFI]

The center of the depression has been moving well to the left of

the previous track, with the initial motion estimated to be 270/05

kt. In addition to the more westward initial motion, there have

been significant changes in the model guidance, with the latest

ECMWF forecast taking the cyclone much farther south and west than

the GFS in 3-5 days. This appears to be the result of enhanced

mid-level ridging to the north of the cyclone in the ECMWF at that

time frame. This has necessitated a significant southwestward

shift of the official forecast, although for continuity the new NHC

track does not take the cyclone as far to the southwest as the

ECMWF. Given the large spread now seen in the dynamical track

guidance, confidence in the track forecast is rather low.

The strong shear over the system is likely to continue for at least

the next 12-24 hours and given the large displacement between the

low- and mid-level centers, no intensification is anticipated in

the short term. The dynamical guidance indicates some relaxation

of the shear in a day or two, so the official forecast shows the

cyclone strengthening into a tropical storm later on Tuesday. This

is close to the intensity model consensus through 48 hours, and a

little below it thereafter. Given the large uncertainty in the

track forecast, there is also uncertainty as to what kind of

environment the cyclone will encounter during the forecast period,

which also leads to low confidence in the official intensity

forecast.

 

 

This probably does NOT  allow an escape .

[AvantHiatus]

There is no escape, the best you can hope for is dissipation or a way south landfall so that you fall outside the wind and surge radius. At this point, the cone is directly centered on the NJ/NY intersection.

 

Hope' because this will not be a 50mph TS at that point.

[jbenedet]

The one common denominator is the long trough interaction and slow WNW to NW motion of TD 11. The surface

reflection in the means is still near the Midatlantic on Monday. It really ends this extended stretch of dull

weather with an exclamation point. October has featured some extreme events in the East since 2005.

 

get_legacy_plot-atls13-95e2cf679cd58ee9b4db4dd119a05a8d-bcG3mC.gif

 

 

I think this uncertainty is MUCH more a function of TD 11's transition, from tropical to extra-tropical. If the upper level dynamics are favorable enough, we could see this make a sharp left hand turn, (think occluded, mid-latitude cyclone), closest to the highest levels of upper level divergence, and PVA.

 

If the upper-level dynamics are relatively weak, this evolves into an intense fropa, juiced with tropical moisture, as TD11 rides along it.

[PB GFI]

Yes, it's either into the Mid Atlantic or NE. It's not going ots.

 

The best we can hope for is a more intense trough to "pull this" inland (much further south and west) as it forces the tropical to subtropical (quasi-noreaster) transition earlier.

I meant MA as a whole , plus 27c water east of 38. Not going to die.

Hooks at 35 ? 38 ? 40 ? To be more clear.

[Superstorm93]

This probably does NOT  allow an escape .

 

 

Banana high to the north...possible ULAC setup if this moves a bit more westward. Could be somewhat interesting, especially if we get another warm-seclusion. 

 

Tropical thread is probably going to be needed once we get the 00z guidance in. 

[AvantHiatus]

In addition, I have my doubts about a Sandy-esque transition. Warm seclusion is very important to consider as the system will be surrounded by relatively tropical PWATS untill landfall.

[Brian5671]

Banana high to the north...possible ULAC setup if this moves a bit more westward. Could be somewhat interesting, especially if we get another warm-seclusion. 

 

Tropical thread is probably going to be needed once we get the 00z guidance in. 

what's an ULAC setup?

[Superstorm93]

what's an ULAC setup?

 

Upper-level anti-cyclonic flow over a tropical system that allows latent heat release and decreases shear.

 

Would favor a much stronger system like the ECM/HWRF/GFDL/UKM are showing 

[Guest Pamela]

There is no escape, the best you can hope for is dissipation or a way south landfall so that you fall outside the wind and surge radius. At this point, the cone is directly centered on the NJ/NY intersection.

 

Hope' because this will not be a 50mph TS at that point.

 

Climatologically, the Sandy path was very anomalous.  These things almost never hook left into Jersey or the Delmarva.  The normal path is either north or northeast...with a landfall on Long Island, Rhode Island, Cape Cod, or just out to sea.  The odds of a left hook are long...but you never know. 

[Superstorm93]

Climatologically, the Sandy path was very anomalous. These things almost never hook left into Jersey or the Delmarva. The normal path is either north or northeast...with a landfall on Long Island, Rhode Island, Cape Cod, or just out to sea. The odds of a left hook are long...but you never know.

But when you have blocking three standard deviations from normal...weird things happen.

Sent from my SM-G925V

 

[Rjay]

Climatologically, the Sandy path was very anomalous. These things almost never hook left into Jersey or the Delmarva. The normal path is either north or northeast...with a landfall on Long Island, Rhode Island, Cape Cod, or just out to sea. The odds of a left hook are long...but you never know.

100% agree with your post but in this case, according many models the blocking will not let this escape and the trough/500mb low will want to pull this towards the coast.

[Derecho!]

Inside 48 I'd take the Canadian short range models above all others...maybe the ECMWF next...maybe some offshoots of the NAM third...like the ARW or NMM...or WRF....they've done pretty nicely in recent years...at least in the winter...not sure of their abilities with tropical systems.

Canadian and NAM are an embarrassing disaster for tropical systems.

the top TC models are consensus averages of EC, GFS, UKMET, etc.

[Guest Pamela]

This is a bit reminiscent of the heavy rains and flooding in early October 2005, stemming from the interaction of post-tropical TS Tammy and a slow-moving cold front.

 

I moved here 21 years ago and this October 2005 rain event still stands as the most outstanding single event I have witnessed during that span (around 20 inches of rain in 3 days)...beyond all the blizzards and everything else. 

 

                    ...WHAT HAPPENED OCTOBER 2005...?

AS MENTIONED EARLIER...LAST MONTH STARTED OUT DRY AND LOCAL AGENCIES

WERE WORRIED ABOUT PREPARING DROUGHT DECLARATIONS. IN FACT...THE

STATE OF NEW JERSEY ISSUED A DROUGHT WATCH FOR THEIR STATE. THE

WEATHER MAP ON THE 7TH SHOWED ALL THE EARMARKS OF CHANGES TO COME.

THE CHARTS SHOWED AN APPROACHING COLD FRONT IN WESTERN PENNSYLVANIA.

THE FRONT WAS SLOWING ITS FORWARD PROGRESS AS IT LABORED AGAINST A

STRONG AND STUBBORN HIGH PRESSURE CELL IN THE WESTERN ATLANTIC. IN

THE UPPER REACHES OF THE ATMOSPHERE...A BUCKLING JETSTREAM WAS

FORMING A CUT OFF LOW PRESSURE SYSTEM HEADING TOWARD THE MID

ATLANTIC STATES. THESE INGREDIENTS MIXED TOGETHER A RECIPE FOR A

WHOLE BUNCH OF RAIN. THE QUARTER INCH OF RAIN WHICH FELL ON THE 7TH

QUICKLY BECAME AN INSIGNIFICANT MEMORY BY DAYS END ON THE 8TH DUE TO

THE 4.26 INCHES THAT FELL THAT DAY! THE BLOCKING HIGH TO THE EAST

CAUSED THE FRONT TO STALL AS IT REACHED THE COAST. UNLIMITED

MOISTURE WAS ALLOWED TO RIDE ALONG IT WITH THE HELP OF LOW PRESSURE

WAVES.

THIS WEATHER PATTERN NEVER REALLY BROKE DOWN EVEN THOUGH THE RAIN

SPUTTERED OUT ON THE 9TH. THE FRONT DID EVENTUALLY MOVE OFF THE

COAST...BUT IT STALLED AGAIN A COUPLE OF HUNDRED MILES TO THE EAST.

THE STRONG BLOCKING HIGH WAS STILL THERE...EVER SO TENACIOUS. THE

BUCKLED JETSTREAM WAS TOO...SUPPORTING ANOTHER CUT OFF BALL OF

ENERGY. AND OF COURSE...THE ATLANTIC OCEAN AND CARIBBEAN SEA WAS

STILL MIGHTY WET! THESE INGREDIENTS WHIPPED UP INTO ANOTHER BOUT OF

HEAVY RAIN. RAIN FELL HEAVILY AT TIMES ALL THE WAY FROM THE 11TH

THROUGH THE 14TH. HEMISPHERIC SATELLITE IMAGES SHOWED CLEARLY THAT

THE MOISTURE SOURCE FOR THIS EVENT COULD BE TRACED ALL THE WAY DOWN

INTO THE TROPICAL LATITUDES...NEAR SOUTH AMERICA! THE HEAVIEST DAY

OF RAINFALL OCCURRED ON THE 12TH...WHEN 4.26 INCHES FELL IN CENTRAL

PARK. READINGS AROUND THE PARK...ESPECIALLY TO THE EAST...SHOWED

EVEN MORE IMPRESSIVE TALLIES.

BY THE END OF THE 14TH...13.25 INCHES OF RAIN HAD FALLEN. THIS

AMOUNT HAD ALREADY BROKE THE RECORD FOR THE WETTEST OCTOBER BY

NEARLY 5 FULL INCHES. COULD MORE FOLLOW...AND COULD OCTOBER 2005

THREATEN THE ALL TIME WETTEST MONTH FOR NEW YORK CITY? RAIN DID

RETURN...DUE TO THE DEVELOPMENT OF A WINTER LIKE WEATHER PATTERN.

THE RAIN ONCE AGAIN BECAME HEAVY. BETWEEN THE 22ND AND 26TH...AN

ADDITIONAL 3.48 INCHES OF RAIN FELL. THE TOTAL NOW STOOD AT 16.73

INCHES...SHORT OF THE RECORD BY 0.12 INCHES! THE LAST 5 DAYS OF THE

MONTH STAYED DRY.

THE FOLLOWING ARE RAINFALL TOTALS FROM THIS PAST OCTOBER FROM

SOURCES ACROSS THE REGION.

LOCATION     OCTOBER RAIN   OLD OCT RECORD     REMARKS

CENTRAL PARK   16.73       13.31 (1903) WETTEST MONTH 16.85 SEP 1882

BRIDGEPORT     12.10       10.72 (1955) WETTEST MONTH 17.70 JUNE 1972

NEWARK         13.22        8.20 (1943) WETTEST MONTH ON RECORD

ISLIP          14.07        8.71 (1989) WETTEST MONTH ON RECORD

JFK AIRPORT    14.97        6.58 (1989) WETTEST MONTH ON RECORD

LAGUARDIA AP   14.71        7.32 (1983) WETTEST MONTH 16.05 AUG 1955

HERE ARE SOME OTHER RAINFALL TOTALS FOR OCTOBER 2005 FROM OTHER

SOURCES.

NWS UPTON LONG ISLAND...21.86.

OCEANSIDE LONG ISLAND...18.26.

CENTERPORT LONG ISLAND...18.69.

$$

MORRIN

[Guest Pamela]

Canadian and NAM are an embarrassing disaster for tropical systems.

the top TC models are consensus averages of EC, GFS, UKMET, etc.

 

 

You may well have more insight into that topic than me...not too much tropical activity for me to get involved with in recent times; hence my lack of familiarity with which models are go-to's in these scenarios.

[PB GFI]

But when you have blocking three standard deviations from normal...weird things happen.

Sent from my SM-G925V

 

If you drive the center into Rehoboth beach , with 8 to 10 inches of rain plus a surge up the Chesapeake Philly/Wilmington  will get hurt .

South of there , Baltimore and Annapolis  have  issues . 

Those high heights could mean left hand turn .  Deep LP does not have to be  a big wind maker to cause problems, 

( this looks to get hung up and not hit the gas coming N , so you are pushing water up against the coastline over time ) , although my fear is with all that warm water , we may start seeing some crazy/stronger op solutions .