Looking Quiet in the Atlantic Again

Former Invest 95L has been struggling mightily in the Atlantic waters. While temperatures have been on the warmer side, wind shear remains high over the region. Enhanced satellite imagery shows a very disorganized area of showers and storms.

Floater IR Enhanced

A westerly wind shear of 20-30 kts continues to batter this disturbance. And that wind shear is expected to increase to near 50kts as a trough moves off the eastern seaboard early next week. Hence, development of this disturbance is not expected.

GFS Wind Shear

Meanwhile, the extremely active East Pacific season continues. Tropical Storm Vance has formed off the southwest coast of Mexico. While it is currently fighting some drier air and moderate wind shear, it is expected to become the 14th hurricane of the East Pacific season (average is 8) as it tracks parallel to the Mexican coastline this weekend into early next week.

ECMWF MSLP and Precip Rate1

By the middle of the week, a trough looks to shear Vance apart as it moves over Mexico. That trough will also pick up the moisture from the storm and move it northeastward into Texas for Wednesday and Thursday.

ECMWF MSLP and Precip Rate2

With only one month left in the 2014 Atlantic Hurricane season, things will likely continue to wind down. We only see typically 5% of named storms forming in the month of November. Having said that, we’ll have to continue being vigilant for any storms out there. In fact, the GFS does bring lower pressure toward the Bahamas late next week so we will watch this closely.

GFS MSL and Precip Rate

Two Year Anniversary of Sandy; Watching Invest 95L in Atlantic

We continue to watch an area of low pressure in the Atlantic. Designated Invest 95L, the disturbance contained a moderate amount of heavy thunderstorm activity, and even a little spin to it. It was located a couple hundred miles north of the Lesser Antilles and drifting to the west-northwest.

Floater IR Enhanced 2

Invest 95L continues to deal with a moderate amount of west-southwesterly wind shear in the 10-20 kt range. Note in the graphic below courtesy University of Wisconsin, wind shear remains on the higher end just to the west of the storm. This will help to prevent the disturbance from organizing much more.

Wind Shear

In addition, the water vapor imagery shows a large amount of dry air just to the west of 95L, which will also make it hard for the disturbance to organize itself.

Florida WV

As we head into the weekend, a large trough will move off the east coast and help to steer 95L to the north and eventually the northeast. Therefore, the system is not expected to pose a threat to anywhere in the US. That trough will also create a more hostile environment for the disturbance with even higher wind shear. Therefore, the NHC only gives 95L a 30% chance to develop in the next few days.

GFS Wind Shear

Invest 95L Models

Today also marks the two-year anniversary of Sandy making a catastrophic landfall in the Northeast. The storm brought record storm surge to multiple sites from the Northern New Jersey shoreline into Battery Park (NYC) and up into coastal New England. This surge caused massive flooding for many coastal communities, some of which are still struggling to recover today. The storm also brought rainfall of up to a foot near Baltimore, and even snowfall amounts near 3 feet to the mountains of West Virginia. Sustained winds were near 80 mph when Sandy made landfall near Brigantine, NJ, though it was no longer fully tropical in nature. Minimum central pressure at landfall was 946mb, tying the Great Long Island Express Hurricane of 1938 as the most intense storm to hit the US north of Cape Hatteras. All in all, the storm caused $68 billion in damage, making it the second costliest hurricane in the US. And the death toll reached 182 in just the US alone (according to the Associated Press).

Sandy Wind

Sandy satellite

 

Hanna Dissipates But Tropical Moisture Lingers Near Central America; Invest 95L Battles Shear Near the Lesser Antilles

Tropical Depression Hanna dissipated Monday night over Central America but tropical moisture will linger for several more days. The former Tropical Storm only survived 14 hours as it was cut off from its moisture source and spent the majority of its lifetime over land. The center was completely disrupted over land and moderate northwesterly wind shear does not favor redevelopment in the extreme northwest Caribbean. Remnant moisture lingers near northern Honduras Tuesday morning and pockets of convection in the northwest Caribbean could induce rainfall in Belize and over the Yucatan later this work week.

Floater IR Enhanced

Officially  remnants of Hanna could bring 3-5″ of rain to Honduras and northern Nicaragua in the coming days. The slug of tropical moisture could also bring tropical downpours to Belize and the Yucatan peninsula. The GFS model (rainfall accumulation graphic below) suggest up to 5″ is possible in Belize by Friday afternoon.

ECMWF-Precip Acc

Elsewhere in the Atlantic a tropical wave pinned Invest 95L moves west northwest just east of the Lesser Antilles early Tuesday. Squalls have reached the islands but they are disorganized. It will be an uphill battle for Invest 95L to significantly organize with a strong trough nearby and another even stronger trough on deck this weekend over the open west central Atlantic. The odds of tropical depression are low over the next 48 hours. The NHC gives the tropical wave a 30% chance of becoming a tropical wave by Saturday.

Floater IR Enhanced 2

Moderate southwesterly wind shear associated with a trough will linger in the open central Atlantic through at least Thursday. The GFS wind shear model shows moderate wind shear directly in the path of Invest 95L through Thursday morning. If the disturbance survives into the weekend another batch of hostile winds is deck as a strong front exits the Southeast U.S. This front will safely guide Invest 95L east of the U.S. and Bermuda.

GFS Wind Shear

Tuesday morning computer models suggest a west-northwest track over the next two days followed by a north-northeast track Friday into the weekend (guided by the second trough).

Invest 95L Models

 

 

 

 

 

Tropical Storm Hanna Forms-Brings Soaking Rains to Central America

Remnants of former TD 9 reorganized over the weekend. The odds were against development but convection gathered in a small region east of Central America with favorable deep moisture and wind shear values. As of 8:30 AM EDT we now have the eighth named storm of the 2014 Atlantic Season-Hanna. Tropical storm force winds extend outward 80 miles from its center and will affect coastal Nicaragua and coastal Honduras Monday. The biggest threat is widespread heavy rainfall.  Hanna drifts west southwest and the center will move inland in Nicaragua this afternoon. It will be cutoff from its moisture source over the next 24 hours and Hanna will become a remnant low by Tuesday morning (if not sooner).

Floater IR Enhanced

Hanna

Computer models have not initialized properly on the amount of rainfall possible in Honduras and Nicaragua through mid-week. Officially 10-12″ is possible with isolated areas picking up close to 15″. There’s also a threat for mudslides. The RPM model below suggests the highest amounts will be right along the coast painting a swath of 7+” in coastal Honduras by Thursday morning.

ECMWF-Precip Acc

Invest 94L Meanders Toward Central America

Invest 94L doesn’t give up in the western Caribbean. Strong high pressure to its north (dry stable air) and a lingering trough (moderate to high wind shear)work against brief tropical depression development . However, there have been some signs of life south of the trough where wind shear values are lower. A batch of convection has briefly organized between Jamaica and Honduras and Nicaragua. If it holds together the weak area of low pressure will generally drift west in the coming days. The odds of development into a brief TD are low due to proximity of land too.

Floater IR Enhanced

Invest 93L Models

Regardless of development tropical downpours are possible especially in coastal Honduras and Nicaragua into early work week. The ECWMF model suggests 3-5″+ of rainfall is possible by Friday morning. Elsewhere in the tropics no development is expected for at least the next five days. Plenty of dry air and hostile upper level winds entrench Gulf and Caribbean.

ECMWF-Precip Acc

 

Broad Low Pressure Lingers in Western Caribbean; Anniversary of 1921 Hurricane

Remnants of Tropical Depression 9 linger in the western Caribbean Saturday. A pesky broad area of low pressure (Invest 94L) stirs up convection between Central America and Cuba early Saturday. The atmosphere isn’t particularly favorable for significant development and the low will likely linger for several more days in this region. The odds of tropical depression development are low over the next five days (10% chance by Monday morning and 20% chance by Wednesday morning per NHC) and tropical moisture will likely stay south of the U.S.

Floater IR Enhanced

Computer models stopped running data on Invest 94L early Saturday morning as the area of low pressure is still quite broad. Nonetheless here is the Friday 0Z run through Wednesday evening. Pockets of deep thunderstorms will linger near Central America into the end of next work week.

Invest 93L Models

While plenty of deep tropical moisture sits in the western Caribbean lots of dry stable air sits just north of this feature in the central and southern Gulf of Mexico. Water vapor imagery shows dry air also sits in the southern Caribbean. With strong high pressure to the north of the broad Caribbean low there is no real storm system to “guide” it. It will meander in the western Caribbean into the work week ahead.

Floater 1 WV

The weak area of low pressure battles moderate wind shear Saturday, however more favorable upper level winds sit on the south side of this feature. If the broad low shifts further south into a lower shear environment it could organize somewhat. The GFS wind shear model shows moderate shear in the Gulf and extreme northern western Caribbean through Monday night with lower shear in the southwest Caribbean. The 06Z GFS suggests a weak closed low drifts back towards Belize and Guatemala on Wednesday. The more reliable ECMWF keeps this feature broad.

GFS Wind Shear

Saturday marks the 93rd anniversary of the last major hurricane to directly hit Tampa Bay. The 1921 Hurricane or Tarpon Springs Hurricane made landfall on this day in 1921 just north Tarpon Springs, Florida with winds of 115 mph, making it a category three hurricane. The most notable damage was caused from the storm surge as this was the worse case storm surge setup with a storm approaching from the southwest. 10-12 feet of water washed through the Tampa Bay area and claimed 10 lives. The 1921 Hurricane also brought 8.5″ of rain to Tampa. It was the most destructive hurricane to hit the region since 1848 and a friendly reminder that late season hurricanes are certainly possible.

1921 Hurricane

Tropical Depression Nine Dissipates But Still Need to Watch

Tropical Depression Nine Dissipated Wednesday night as it moved over the Yucatan Peninsula. While still expected to bring soaking rains to that area (5″-10″+), the disturbance no longer looks organized enough to be considered a depression. In fact, a look at the enhanced satellite imagery from Thursday morning doesn’t show much over the Yucatan. Rather the heavy thunderstorm activity moving into the western Caribbean is far removed from the actual broad area of low pressure, which is still over the Yucatan.

Floater IR Enhanced

Despite having dissipated, we will still have to watch the remnants of TD9 once it emerges into the western Caribbean. Over the last few days, models have been trying to develop the remnants into something that would move into the Gulf. However, today, all of those models have backed off and no longer show any development. Below are the ECMWF (Euro) and the GFS; note neither shows any re-development of TD9.

ECMWF vs GFS MSLP and Precip Rate

As for one of the reasons why re-development is unlikely, we have to focus in on precipitable water values which measures the amount of available moisture in the atmosphere. As we head into the weekend, a big trough will help to drag dry air through the Gulf and into the western Caribbean. Notice the abnormally dry air (denoted by shades of yellow and brown) by the weekend sitting in the Gulf.

Precipitable Water

That same trough will bring higher wind shear into the picture through the weekend and into early next week. This will produce a very unfavorable environment for development or re-development in the Caribbean.

GFS Wind Shear

In addition, sea surface temperatures in the Caribbean are actually at or slightly below average for this time of the year. Having said that, if anything did spin up into the Gulf next week, SST’s are running well above average and would provide plenty of fuel for development.

sst_anom_avhrr_amsr_carib

 

Tropical Depression 9 to Soak the Yucatan; Uncertain Long-range Forecast

Tropical Depression 9 maintains strength in the Bay of Campeche Wednesday morning as it slowly drifts eastward. The structure of the tropical depression is still disorganized due to moderate westerly shear and dry air over the central Gulf. However, Hurricane Hunters continue to find a well-defined center of circulation. If enough convection organizes near its center Tropical Storm Hanna could form briefly by tonight before it moves over the Yucatan Thursday. Notice the deepest convection on enhanced satellite imagery is not associated directly with Tropical Depression 9. A huge slug of tropical moisture nears western Cuba and south Florida through the end of the work week and dumps heavy rain on the region.

Floater IR Enhanced

Future Tropical Storm Hanna is set to dump 5-10 inches of rain (isolated areas will see up to 15 inches) on the Yucatan peninsula in the coming days. The storm will obviously be disrupted by land interaction (should briefly dissipate) through Friday. Whatever is left of Tropical Depression 9 will interact with a trough through the weekend and possibly into next week over the western Caribbean. While wind shear values will be somewhat lower atmospheric conditions aren’t perfect for tropical cyclone development. The graphic below is the 11 AM advisory.

TD 9

Parts of south Florida catches a break from Tuesday’s flooding rains early Wednesday. More downpours drench the Keys and will affect Southeast Florida too through early Saturday. This moisture is not directly associated with Tropical Depression 9. The Weather Prediction Center estimates up to 3.5″ is possible near or just south of the Florida Keys by Saturday morning.

Florida Satellite-Radar Weekend AM

qpf2

The long-range forecast for Tropical Depression 9 is especially complicated. Recent computer models suggest that while a “piece” of the storm will be carried towards the Bahamas and out to sea over the weekend (as a trough lifts out of the Caribbean ) a greater “piece” of energy could linger in the western Caribbean. Computer models are split between a meandering broad low in this region into mid-week next week and a stronger tropical low lifting north towards Cuba and possibly Florida. The graphic below is the 12Z model run through Tuesday night.

Invest 93L Models

It’s early but it appears the reliable ECMWF model wins the battle of the models so far. The 0Z run suggests a broad low lingers in the western Caribbean through next work week under the influence of strong high pressure over the Southeast U.S. The GFS model has been back and forth. The 12Z run is more in line with the Euro and keeps pressure generally low in the western Caribbean through mid-week next week. Interest in the Caribbean and south Florida should monitor the progress of TD 9 in the coming days.

Euro vs GFS

 

 

Tropical Depression 9 forms

TD # 9 has formed in the Bay of Campeche. It is still disorganized, and it moving to the east very slowly.ir_enhanced_storm1_1 Before it moves onshore, it could become Tropical Storm Hanna. The short term forecast is simple, but the log term becomes more complicated. As it moves into the Western Caribbean, a piece of it may be left behind.trackmap_storm1 So keep it right here for the very latest.

Invest 93L Attempts to Organize Near the Yucatan Peninsula; Extended Wet Period for South Florida

Invest 93L attempts to organize as it near the Yucatan peninsula Tuesday. The odds of development per the NHC sit at 50% by Thursday afternoon and 50% over the next five days. Hurricane Reconnaissance Aircraft found a small well defined center this afternoon but convection isn’t organized enough for Invest 93L to be upgraded to a tropical cyclone. Moderate westerly shear pushes the deepest convection towards the Yucatan but a huge slug of tropical moisture brings pockets of heavy rainfall up towards south Florida (especially over the Keys). Models generally bring Invest 93L east-northeast in the coming days. The question remains if the area of low pressure lingers in the northwest Caribbean for a while or it gets picked up by a trough and carried out to the open western Atlantic this weekend. The bottom line is regardless of development an extended wet periods is expected for the Yucatan, Cuba, and south Florida.

Fly to Gulf Disturbance

Invest 93L Models

The GFS model brings 7+ inches of rainfall to Key West and about 6″ to Miami by Saturday afternoon. These totals may be a little overdone as recent model runs keep Invest 93L further south. The Weather Prediction Center estimates t 5+” is possible in Key West by next Tuesday in their 7 day outlook. Areas south of Tampa Bay will also see enhanced rainfall but the hefty totals stay south of Ft Myers. The further south Invest 93L stays the less rainfall south Florida will see.

GFS-Precip Acc

The 0Z ECMWF and 06Z GFS are in pretty good agreement through Friday. Deep moisture brings steady rainfall to south Florida and west Cuba into Friday afternoon. The area of low pressure stays weak/possibly just broad in nature near the Florida Straits and northwest Cuba. With a stalled frontal boundary nearby enhanced wind shear will make it tough for Invest 93L to deepen significantly.

ECMWF vs GFS MSLP and Precip Rate

Tropical moisture looks to exit south Florida early Saturday. By early Sunday morning both the 0Z ECMWF and the 06Z GFS track low pressure northeast into the open western Atlantic. The Euro does keep a small “piece” of low pressure behind in the western Caribbean. If this is valid tropical downpours could linger in the western Caribbean into next work week.

ECMWF vs GFS MSLP and Precip Rate.png 2