Flooding

Coastal Storm Wednesday Evening Update

Miguel Pierre Flooding, Short-Term

This morning an inverted trough from coastal storm developing, gave New York City, Western Long Island and parts of New Jersey, some heavy rain and thunderstorms. A lull activity occuring for most of tri-state earlier this afternoon. But the coastal storm deepening and moving slower back to the coast this evening. Bands of rain with some embedded convection is now rotating back into Tri-State area.  Winds have been increasing has well, a little more than expected. Some coastal locations have sustained winds 20-30mph with gusts 30-40mph. Just east of the area, Block Island and Buzzard Bay have reported wind gust up to 45mph. Buoy south of LI have gusts to 49mph and 51mph. The highest winds are likely being brought down from aloft by thunderstorms, currently offshore. A cold pool aloft with this storm and as well warmer than normal sea-surface temperatures is enhancing instability near and off the coast. Radar has also detected rotation some of these thunderstorms today. Helicity along with instability may some waterspouts to form. But as these storm move closer to land, they have weakened somewhat, as they enter less unstable airmass.

Surface wind, temps with radar overlaped at 6:43pm EDT
Surface wind, temps with radar overlaped at 6:43pm EDT

I expect bands of rain to continue to work their way inland from the ocean tonight and tomorrow. Some thunderstorms are still possible tonight. The 21z RAP shows 925mb winds at 40-50kt+ across coastal areas tonight. Heavy showers or thunderstorm could bring some of these winds down to surface, near the coast. Otherwise still not this storm, to much more than nuisance across the area. Tidal flooding should no be a\ issue along most coastal locations as winds are switching to the north and northwest. The only exception may be over parts of the north shore of Long Island or other north-facing shorelines.

21z RAP from College Dupage Site
21z RAP from College Dupage Site show 40-50kt winds from New York City, Long Island northward

This storm will be weaken pull away from Thursday night and Friday. With slow clearing taking place. This weekend still appears to be mostly dry.

Heavy Rains Tonight for NY Tri-State Area, Hurricane Gonzalo A Threat to Bermuda

Miguel Pierre Flooding, Short-Term, Tropics

Rain has held off for the tri-state most of the day. Warm and breezy conditions remained, and clouds even broke for some sunshine. But that looking at radar now, that is quickly changing.

A large cut-off area of low pressure moving east from the Ohio River Valley will continue to cause rain to spread east over the Tri-state area tonight with some heavy downpours and embedded  thunderstorms. Associated cold front and a strong southeasterly flow with this storm system, will bring an abundant amount of moisture, lift, and some elevated instability. Rainfall totals of 1″ – 2″ are expected for much of the area.  However some training of heavy rains or thunderstorms may also occur and produce heavier rainfall totals, in some spots. Precipitate water values support 1.50″ to 2.00″ suggests very heavy rainfall is possible in a short period of time. The main threat from this system is flash flooding in poor-drainage and low-lying areas. Some heavier showers or thunderstorms may bring down stronger winds aloft, in the form of wind gusts up to 40mph.  But southeast winds off the ocean, will keep surface-based instability on low side. So severe weather is not anticipated in the Tri-state area.

18z HRRR today showing band of heavy rain or thunderstorms moving into the Tri-State area overnight
18z HRRR today showing band of heavy rain or thunderstorms moving into the Tri-State area overnight

As the cold front moves slowly across the region, rain with heavy downpours will be begin to taper from west to east during the day  Parts of Long Island and Connecticut may however see steady and heavy rain into the afternoon hours.   Cooler and drier weather should arrive on Friday and Saturday with temperatures seasonable. An even cooler airmass from Canada, will arrive behind another cold front on Sunday. High temperatures on Sunday and early next week, may only be in the lower to middle 50s, even with alot of sunshine. Temperatures on Sunday night may also be fall into the lower 40s or 30s. Some parts of the area may see their first frost or freeze. Especially over Northwest New Jersey and Lower Hudson Valley:

 

12z GFS showing temperatures in the 30s over the tri-state area Sunday night.
12z GFS today showing temperatures in the 30s over the tri-state area Sunday night.

 

Meanwhile Hurricane Gonzalo  became a category 4 hurricane today winds of 130mph as it moves northwest over the Southwest Atlantic. The storm is expected to turn northeast into the open North Atlantic this weekend. However, it may pass very close to Bermuda as major hurricane, before doing that, on Friday.  As of 5pm EDT, the National Hurricane Center has issued a hurricane watch for Bermuda. Gonzalo weakened slightly to catergory 3 hurricane with 125mph winds. But is forecast to be category 3 hurricane very close to Bermuda at 2pm Friday. High swells, possibly up to 10ft, from Gonzalo will also reach the New Jersey and Long Island shores by Friday night and Saturday. Stay tuned more updates here on this storm through Saturday.

 

Visible image late this afternoon of Hurricane Gonzalo
Visible image late this afternoon of Hurricane Gonzalo

 

Coastal Storm to Bring Heavy Rain and Winds to The Tri-State Area

Miguel Pierre Flooding, Forecasts, Short-Term

Coastal storm is now taking shape along the East Coast. It’s weak, disorganized storm. But this system is pulling lots of moisture from the Atlantic and Gulf of Mexico. This will give parts of Tri-state area some heavy rainfall. A strong high east of New England will also create a tight pressure gradient between this system.  Resulting in windy conditions and some minor coastal flooding tomorrow as well. Check out more details below.

et0z3

Rainfall Totals:

There is some uncertainty, in how much rain will fall out this system. The model guidance is struggling with areas of convection off the east coast and some subsidence over Northeast. Right 1-2″ seems to be good bet for much the area. However amounts may vary greatly from area to area, depending on how heavy rain bands move through the area. Most guidance has good theta- advection and frontogensis with very high precipitable water values, lifting northward through the area late tonight and tomorrow. This is when heaviest rainfall will likely occur. Tomorrow afternoon these dynamics begin to weaken and lift northward. So some periods of lighter rain and drizzle is expected. This may linger into tomorrow night for Derek Jeter’s last home game at Yankee Stadium. But I think they will probably still play.

Rainfall Totals 092514

Winds & Coastal Flooding:

The low pressure with this storm is weak. But with a strong high east of New England, there will be a tight pressure gradient. This will cause winds out the east to northeast to increase between 25 to 35mph with gusts up 45mph,  along the New Jersey, Long Island and Connecticut shores. Just inland winds over NYC, Northeast NJ and Long Island will 15 to 25mph with gusts to 35mph. Further northwest winds will be weaker. With the new moon, these winds will cause some minor coastal flooding at high tides tonight and tomorrow morning. As well as some high waves and rip currents at the shore too. Buoy 44009 about 25 miles southeast of Cape May, NJ is already report waves up to 10ft this evening.

Wind Forecast 092514