Record 24hr Rainfall NY State - Long Island Flooding (snow, warm, records)

[Cambium]

Instead of reposting stuff, here's the start of the posts this morning regarding the weather and flooding.

https://www.city-data.com/forum/weath...l#post36061235

First... Gotta love those lovely computer models picking up the pattern and scenario from 7-10 days out..

Originally Posted by Cambium

How many times have I said "This doesn't usually happen in the summer"? (at least in the past 50yrs only) Well, how about again?

Euro says next week a strong low curls around the base of the trough heads into Great Lakes then transfers energy into a coastal storm and heads into Maine...

These senarios better get saved for winter!! Major snowstorm if this was winter except for coast with particular this setup. But because we're in August it's a lot of rain instead.

[Cambium]

Second...

The records... Not just daily.... not just monthly...but entire State record broken

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE NEW YORK NY
447 PM EDT WED AUG 13 2014

...RECORD DAILY MAXIMUM RAINFALL SET AT ISLIP NY...
A RECORD RAINFALL OF 13.21 INCHES WAS SET AT ISLIP NY TODAY AUGUST 13.
THIS BREAKS THE OLD RECORD OF 0.91 SET IN 2013.


...RECORD NEW YORK STATE 24 HOUR PRECIPITATION BROKEN AT ISLIP
MACARTHUR AIRPORT TODAY...

A PRELIMINARY NEW YORK STATE 24 HOUR PRECIPITATION RECORD WAS BROKEN
AT ISLIP LONG ISLAND TODAY. TOTAL 24 HOUR PRECIPITATION AT ISLIP AS
OF 9:30 AM WAS 13.26 INCHES. THIS BREAKS THE PREVIOUS RECORD OF 11.6
INCHES AT TANNERSVILLE NY ON AUGUST 27-28 2011 DURING
HURRICANE/TROPICAL STORM IRENE.

THE 24 HOUR PERIOD FOR THIS RAINFALL EVENT WILL END AT 11PM ON
AUGUST 13. THIS REPORT WILL BE UPDATED AFTER MIDNIGHT FOR ANY
ADDITIONAL RAINFALL THAT MAY FALL.

THIS RECORD WILL REMAIN PRELIMINARY UNTIL THE NATIONAL WEATHER
SERVICE AND THE NATIONAL CLIMATIC DATA CENTER CONFIRMS THESE
REPORTS.


A RECORD MAXIMUM MONTHLY RAINFALL FOR THE MONTH OF AUGUST OF 13.88
INCHES WAS SET AT ISLIP NY TODAY. THIS BREAKS THE PREVIOUS RECORD
OF 13.78 INCHES SET BACK IN AUGUST OF 1990.


THESE REPORTS ARE PRELIMINARY AND WILL BE UPDATED LATER IF AND WHEN
MORE RAIN FALLS AT ISLIP.

[Cambium]

Third... The Setup

Just the luck of the draw who is under the heaviest axis. Same goes for Winter snowstorms. Hard to predict and forecast since it's a localized thing.

Here is this mornings map. To keep this simple.. Upper Level winds and storm direction was moving Northeast. Surface winds were from the Atlantic from the East! See it?

This created convergence near Long Island. Extra lift that pumped more liquid into the atmosphere. Add the fact that the atmosphere was already loaded with moisture and it drops like a ton of bricks.

Considering the fact that we had a warm front in the area and a coastal storm and being its August with warm ocean waters it doesn't surprise me we saw areas get over 7" of rain.

[Cambium]

From Ryan Maue:

"Low pressure of sub-1000 mb is intense and rare/unusual for mid-August in Northeast US thanks to Canadian vorticity. "

Yup, that Upper Level Low in Canada spawned the coastal storm and those East winds that helped the cause.

[Cambium]

7pm Radar. Downpours heading across Long Island.

Islip needs 1.55" more to beat NJ's State 24hr precip total of 14.81"

Massachusetts State 24hr precip record is August 18-19, 1955 of 18.15"!

[Cambium]

Heavy Thunderstorm rain over Islip right now. More rain!! Are they going for the Gold?

[Cambium]

Just an unbelievable scene here in Islip on Long Island this morning! sunrise highway

https://twitter.com/WeatherGoneWild/...821696/photo/1

[Cambium]

Want crazy?

ISP went from 5th driest Summer on record to now Top 5 wettest summers so far.

Isnt it crazy that when we look at data we don't see the true detailed events? We'll look back at 2014 and see a very wet summer there unless we look into the details that 1 day did it. Crazy

This was as of yesterday, now have 19"

[irlinit]

18 inches is not too far away from our yearly total! Wow

[nei]

Originally Posted by Cambium

7pm Radar. Downpours heading across Long Island.

Islip needs 1.55" more to beat NJ's State 24hr precip total of 14.81"

Massachusetts State 24hr precip record is August 18-19, 1955 of 18.15"!

That was from Hurricane Diana, as is usual with late summer / early fall rainfall events. The impressive thing to me is that no tropical storm or tropical storm remnants were involved. Though a tropical storm probably would have led to more widespread rainfall. Anyhow, here's a record of the rainfall for that day in Islip. Note most of the rain was in four hours, 2/3rds or so (9.7" in 2 hours):