How’s the Weather Cruising the North Atlantic during July?

July Pilot Chart

PILOT CHART NORTH ATLANTIC JULY

Overview

During the month of July, the Azores to Bermuda High dominates the North Atlantic weather extending from the North Sea to the Gulf of Mexico with a mean center near 35N/35W.    Storm tracks have shifted north of 50 North latitude, except for one primary track from off the Carolina Coast northeastward towards the Denmark Strait. 

Fog occurrence during July is 10% or higher north of a line from Long Island to Ireland. July is also the foggiest month of the year over the Grand Banks with a 40% to over 50% risk for visibility of 2 miles or less. Icebergs can still be found southeast and east of Newfoundland during July 

Wind and Waves

South of the Azores-Bermuda high to about 10 N latitude, winds tend to be from the northeast to east averaging Beaufort force 4 (11-16 knots) with waves mostly about 1-1.5 meters (3-5 feet),  except winds tend to be more northerly off the coasts of Iberia and northwestern Africa. Northeast to east winds average Beaufort Force 5 (17-21 knots) with waves around 2 meters (6-7 feet) prevailing over the central Caribbean Sea. South of 10 N, winds are more likely to be from the south at Beaufort Force 3 (7-10 knots) with waves 0.5 meters (2 feet) or less. 

North of the Azores-Bermuda high winds tend to be mostly from the southwest to west averaging Beaufort Force 4 (11-16 knots) with waves mostly about 1-1.5 meters (3-5 feet).

Gale Risk

July Surface Pressure, Storm Tracks and Gale Risk

July Surface Pressure, Storm Tracks and Gale Risk

The risk of encountering gale force (Beaufort Force 8/34 knots) or higher winds is near zero south of about 35 N latitude this month.  Between 35 N and 50 N latitudes, the risk for gales is low at 1% or less and north of 50 N latitude the risk is only 1-4 %. 

 

Temperatures

The air temperatures range from 4 C (39 F) in the Davis Strait to about 28 C (82 F) over the Southwest North Atlantic, Gulf of Mexico and Caribbean Sea.  Sea surface temperatures range from under 5 C (41 F) in the Davis Strait to about 28-29 C (82-84 F) in Gulf Mexico, Caribbean and the southwestern North Atlantic.

Tropical Cyclones

There is an increasing risk for tropical cyclone development during July with the highest risk (14%) occurring in the north-central Gulf of Mexico. 

Pilot Chart TC Frequency North Atlantic July

Pilot Chart TC Frequency North Atlantic July

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How’s the Weather cruising the Caribbean and Gulf of Mexico during July?

July Piot Chart

NOAA Atlas of Pilot Charts for Gulf of Mexico and Caribbean in July

Wind

Caribbean Sea
Easterly winds mostly Beaufort force 4 (11-16 knots) prevail this month, except forces 4-5 (11-21 knots) prevail over the central Caribbean north of Columbia. Over the southwestern Caribbean the wind will back east to northeast and diminish to forces 3-4 (7-16 knots) and over the northwestern Caribbean, winds tend to be from the east forces 3-4 (7-16 knots).  There is a low (about 1%) risk for encountering gale wind forces 8-9 (34-47 knots) over the central Caribbean north of the Columbian coast during July. 

Gulf of Mexico
East to southeast winds, mostly forces 3-4 (7-16 knots) prevail, except becoming more variable in direction forces 2-3 (4-12 knots) over the Northeast Gulf and southeast to south forces 3-4 (7-16 knots) over the Northwest Gulf.

Waves

Generally waves average 2-5 feet (0.5-1.5 meters), however, over the Central Caribbean 6-8 foot (2-2.5 meter) waves will prevail. The risk for rough seas of 8 feet (2.4 meters) or higher is less than 10% across the Gulf of Mexico, the northwestern and the easternmost Caribbean, however, the risk increases to 30-45% over the central Caribbean Sea, especially north of Columbia. 

Temperature 

Over the Gulf of Mexico air temperatures average around 82-84 F (28-29 C) over the Gulf of Mexico and 81-83 F (27-28.5 C) across the Caribbean. 

Land Temperature
Overall, most Caribbean destinations see morning lows of 74-80 F (23-27 C) during July with daytime highs mostly 86-92 F (30-33 C). The hottest locations are Aruba, Cancun, Cozumel and the Caymans with afternoon high temperatures averaging at or above 90 F (32 C). 

Tropical Cyclones

There is an increasing risk for tropical cyclone development during July with the highest risk (14%) occurring in the north-central Gulf of Mexico. 

NOAA Pilot Chart Tropical Cyclone Frequency North Atlantic July

 

 

 

 

 

 

 

 

Rainfall

Rainfall during July varies quite a bit from 1.2 inches in Aruba to about 9.6 inches in Belize. The wettest locations include Belize, Bahamas, Trinidad, Dominica, St. Lucia and Martinique.  Drier locations include Aruba and Curacao, Cancun, Montego. St. Maarten, and St. Thomas.  

 

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2022 North Atlantic Hurricane Outlook

Hurricane Dorian

NOAA image of Hurricane Dorian, Cat. 5 off the Florida coast taken at 13:20Z September 1, 2019

The 2022 North Atlantic Hurricane Season officially begins on June 1st and ends on November 30th. During the most recent 30-year period (1991-2020) there has been, on average, about 14-15 named tropical cyclones.  Of these, about 7-8 become hurricanes and 3-4 become major hurricanes. NOAA has recently published their Seasonal Hurricane Outlook calling for increased activity again this hurricane season. The prediction for another active season is attributed to several climate factors, including the ongoing La Niña that is likely to persist throughout the hurricane season, warmer-than-average sea surface temperatures in the Atlantic Ocean and Caribbean Sea, weaker tropical Atlantic trade winds and an enhanced west African monsoon. 

2022 outlook

NOAA 2022 Atlantic Hurricane Season Outlook

For the 2022 hurricane season, NOAA is forecasting a likely range of 14 to 21 named storms, of which 6 to 10 could become hurricanes, including 3 to 6 major hurricanes (category 3, 4 or 5). The range of total named storms (14-21) is provided with a 70% confidence.  The predicted range runs from near normal to well above normal which suggests that there is still a good bit of uncertainty for this upcoming season.

Listing of 2022 Atlantic Hurricane Season Outlooks

Sea Surface Temperature Trends

Among several important factors cited in the NOAA outlook are “warmer-than-average sea surface temperatures in the Atlantic Ocean and Caribbean Sea”. The one outlier among the various projections is the outlook from the University of Arizona which  expects this season not to be as active as last season, however, they expect to review their outlook in early June based on more reliable sea surface temperatures.  

Sea Surface Temperature Anomaly North Atlantic

Tropical North Atlantic and Caribbean Sea Surface Temperatures (SST) have cooled recently as we approach the start of the North Atlantic Hurricane Season on June 1st.  In the Atlantic Main Development Region (MDR) SSTs cooled from mid-February to mid-April, followed by a warming trend into the second week of May which recently has reversed.   Only the Gulf of Mexico and southwestern portion of the North Atlantic has remained abnormally warm.

The cooling trend, “IF IT CONTINUES”, will have the effect of reducing the amount of tropical cyclone activity this season, compared to last season.   We shall see!

Sea Surface Temperature Anomaly Trend for the Main Development Region

 

Sources

Colorado State University
Tropical Storm Risk
University of Arizona
NOAA
Accuweather
Accuweather
UK Met Office
NC State University
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What to expect transiting the Indian Ocean during June

June Pilot Chart

NOAA Pilot Chart Average Surface Pressure and Tropical Cyclone tracks over Indian Ocean in June

 

South Indian Ocean

A ridge of high pressure normally extends from South Africa eastward to the west coast of Australia, mainly between 25-30 south latitudes. Southward of about 35 south latitude, westerly winds prevail averaging forces 5-6 (17-27 knots) with significant wave heights generally 2-3 meters.  Northward of the prevailing ridge, winds tend to be from the southeast averaging force 4-5 (11-21 knots) with waves mostly 1.5-2 meters, becoming southeast to south forces 3-4 (7-16 knots), waves 0.5-1 meter nearing the equator. 

The risk for encountering gale force (BF8/34kt) or higher winds is 10% or less from the equator to about 35 S latitude then increases from 10% to 26% southward of 35 S.  The risk of encountering waves of 12 feet (3.7 meters) or higher is 30-40% from about 40S southward, diminishing to  20-30% near 30 S and generally 15% or less north of 20 S latitude. 

North Indian Ocean 

Arabian Sea

The Southwest Monsoon establishes itself in June and the frequency of gales increases rapidly over the western half of the Arabian Sea reaching over 10% with the highest risk near 14 N 57 E.

June Monsoon

Monsoon over Arabian Sea during June

The risk of encountering waves of 12 feet (3.7 meters) or more increases over this area from less than 10% in May to as high as 40% or more in June. In the same area there is also a 5% risk of encountering waves of at least 20 feet (about 6 meters). 

Bay of Bengal

Generally a southwest monsoon prevails in June, averaging forces 4-5 (11-21 knots) with waves mostly 1.5-2 meters.

Tropical Cyclones

Cooler temperatures in the southern hemisphere in June reduce the risk for tropical cyclone development to less than 1 every decade. Over the North Indian Ocean there is a 70% risk for tropical cyclone development and mostly confined to the eastern Arabian Sea and Bay of Bengal.  

June IO Pilot Chart

NOAA Atlas of Pilot Charts for Indian Ocean in June

 

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What’s the weather like cruising the Caribbean and Gulf of Mexico during June?

JUNE

ATLAS OF PILOT CHARTS JUNE

Wind

Caribbean Sea
Easterly winds mostly Beaufort force 4 (11-16 knots) prevail this month except force 5 (17-21 knots) over the central Caribbean north of Columbia. Over the southwestern Caribbean the wind will back more into the northeast and diminish to mostly forces 3-4 (7-16 knots). Over the northwestern Caribbean, winds tend to be more from the east to east-southeast force 4 (11-16 knots).

Gulf of Mexico
East to southeast winds, mostly forces 3-4  (7-16 knots) prevail.

Waves

Generally waves will average 2-5 feet (0.5-1.5 meters) however, over the Central Caribbean, waves average 6-8 foot (2-2.5 meters).  The risk for encountering rough seas of 8 feet (2.4 meters) or higher is less than 10% across the Gulf of Mexico, the northwestern and easternmost Caribbean, however, the risk increases to 20-30% over the central Caribbean Sea, especially north of Columbia. 

Temperature 

Over the Gulf of Mexico air temperatures average near 81-84 F (27-29 C) over the Gulf of Mexico and the western and central Caribbean Sea but 80-82 F (27-28 C) over the eastern Caribbean.

Overall, most Caribbean destinations see morning lows of 74-80 F (23-27 C) with daytime highs 86-92 F (30-33 C). The hottest locations are Aruba, Cancun, Cozumel and the Caymans with afternoon high temperatures averaging at or above 90 F (32 C). 

Sea Temperature 

Sea surface temperatures average 81-83 F (27.5-28.5 C) for most of the Gulf of Mexico and Caribbean Sea this month, except 80-82 F (27-28 C) in the eastern Caribbean.

Rainfall

Rainfall continues to increase in the Caribbean during June, however, Aruba remains dry with Antigua and St. Maarten also being relatively dry this month. Higher rainfalls are likely in Central America, especially Belize and Costa Rica.  In addition, the Bahamas also see heavier rainfalls during June.

 Tropical Cyclones

The risk for tropical cyclones increases in June with the highest risk (10-17%) occurring over the Gulf of Mexico and an 8-11% in the Northwest Caribbean Sea. The risk diminishes to 3-5 % for the Southwest Caribbean and 2% or less for the eastern Caribbean. 

TC Risk June

Frequency Occurrence of Tropical Cyclones in June  (SST shown in Green)

 

 

 

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North Atlantic Weather Routes limited by Icebergs

500 mb chart

NOAA OPC 72 hour 500mb Forecast Chart

Upper-level blocking over the northeastern North Atlantic into northwestern Europe and a large cut-off low over the central North Atlantic, south of 40N latitude, will persist for the next few days. This pattern will allow for relatively light easterly winds and seas to persist across the North Atlantic north of  45N while strong to gale conditions persist south of 45N all the way down to 25N over the west-central North Atlantic. 

NOAA OPC 72 hour Surface Forecast

This pattern should allow shorter great circle routes between North Europe and the US East Coast, however, at this time the North Atlantic icebergs are drifting southward off of Newfoundland to near 45 N latitude limiting the shorter route options to keep clear of the icebergs.

North Atlantic Iceberg chart via North American Ice Service

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What’s the weather like cruising the Caribbean and Gulf of Mexico during May?

satellite

Gulf of Mexico and Caribbean Sea

The weather cruising the Caribbean and Gulf of Mexico during May is excellent with light to moderate winds and low risk for gales.

Wind

East to Northeast trade winds of Beaufort forces 3-4 (7-16 knots) prevail across the Caribbean during May with somewhat higher winds of Beaufort forces 4-5 (11-21 knots) prevailing off the coast of Columbia. Over the Gulf of Mexico, east to southeast winds of Beaufort forces 3-4 (7-16 knots) prevail, except east to northeast winds in the Bay of Campeche.  The risk for gale force winds is very low for both the Caribbean and Gulf of Mexico this month. 

Pilot Chart of the Gulf of Mexico and Caribbean Sea for May

Waves

The risk for rough seas of 8 feet (2.4 meters) or higher is less than 10% across the Gulf of Mexico, the northwestern Caribbean and the easternmost portion of the Caribbean. This risk increases to 10-20 % over the central Caribbean Sea with a somewhat greater than 20% risk concentrated off the coast of Columbia. 

Temperature 

Over the Gulf of Mexico air temperatures average near 77 F (25 C) over the northwestern Gulf, warming to around 80-81 F ( 27 C) in the Bay of Campeche and near the Yucatan Channel.  In the Caribbean, air temperature averages around 80-81 F (27 C) throughout. Most destinations in the Caribbean will experience daily morning low temperatures ranging from 74-80 F (23-27 C)  with afternoon high temperatures 80-92 F (30-33C).

Sea Surface Temperature 

Sea surface temperatures average around 77 F (25C) over the northwestern Gulf, increasing to 81-82 F (27-28C) over the Bay of Campeche and near the Yucatan Channel.  In the Caribbean, sea temperatures are mostly 81-82 F (27-28 C) with the warmest waters over the westernmost Caribbean. 

Rainfall

May begins the rainy season in the western Caribbean, including Cancun, Cozumel, Grand Cayman, Jamaica as well as parts of the Bahamas. Drier conditions remain in most of the eastern and southern Caribbean locations, although rainfall amounts start to increase in the Windward Islands.

Tropical Cyclones

The risk for tropical cyclones

Frequency of Tropical Cyclones in 5-Degree Squares during May

begins to increase this month with a 1-3 % risk for encountering a tropical cyclone over the Gulf of Mexico and western Caribbean Sea. The risk remains 1% or less over the eastern Caribbean. 

 

 

 

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Tropical Cyclone Halima now a Cat 4 Storm

tc Halima

Tropical Cyclone Halima over the South Indian Ocean

Tropical Cyclone Halima over the South Indian Ocean has intensified into a Category 4 hurricane with max winds of 120 knots and significant wave heights to 35 feet (10.7 meters).

 

 

 

 

 

 

Halima is moving south-southwest at 5 knots and is forecast to track southward over the next 36 hours with additional intensification to near 130 knots over the next 12 hours.

Thereafter, Halima should turn more towards the southeast then east with gradual weakening.

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North Atlantic Maritime Weather Outlook

500 mb

NOAA OPC 72 hour 500 mb Forecast

An upper-level ridge will build near and over Ireland during the next few days resulting in a strengthening surface high pressure area which will block North Atlantic storms from Northern Europe.

 

 

 

At the same time, a cut-off upper low near Morocco, will enhance surface low pressure over northwestern Africa causing strong to gale force winds and rough seas over the western Mediterranean Sea.    

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sfc fcst

NOAA OPC 72 hour Surface Forecast

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What can we expect for the 2022 Atlantic Hurricane Season?

Hurricane Dorian

Visible satellite image Hurricane Dorian Sept. 1, 2019 making landfall on Elbow Cay in The Bahamas. Image credit: NOAA/RAMMB

Will 2022 bring yet another very active hurricane season or will it be more in-line with the long-term average of 12-13 named storms, 6-7 hurricanes and 2-3 major hurricanes? 

The Sea Surface Temperatures (SST) over the Atlantic Main Development Region (MDR)  have been cooling since mid February,  especially in the eastern half of the region.  More than half of all hurricanes and nearly 80% of major hurricanes develop in the MDR, so if this cooling trend continues, fewer major hurricanes will develop this season. Development of tropical cyclones requires heat energy from the ocean surface and generally requires SSTs of at least 26.5 C (80 F).

MDR

North Atlantic Main Development Region

 

 

 

 

 

 

 

 

In recent years we have seen a cool pattern of SST anomalies develop during the winter months over the MDR. particularly over the eastern half, only to have temperatures return to warmer than normal during the late summer and autumn months. The question is will this pattern repeat itself this year or not?  

 

 

 

 

 

 

An important factor driving an active versus inactive Atlantic hurricane seasons is the strength of the Atlantic multi-decadal oscillation (AMO).  

amo

Atlantic multi-decadal oscillation (AMO)

The AMO is a series of long-duration changes in the sea surface temperature of the North Atlantic Ocean, with cool and warm phases that may last for 20-40 years at a time. These changes are natural and have been occurring for at least the last 1,000 years. A positive (warm) phase of the AMO can result in a season that has 3-5 times more major hurricane activity than does a negative (cool)  phase. The phase of the AMO also has a strong correlation with the number of hurricane landfalls striking Florida, the U.S. east coast and the Caribbean.

During the last cool phase of the AMO (about 1970-1995) tropical cyclone activity was suppressed compared to the current and previous warm phases.  Since the mid 1990s the warm phase of the AMO has prevailed, characterized by some record setting hurricane seasons including many notable landfalls.  Given that the last AMO phase shift (Cool to Warm) occurred over 25 years ago, the shift back to the cool (from the current warm phase) is likely within the next 5-7 years and when this occurs, we will experience a reduction in Atlantic tropical cyclone activity. 

North Atlantic Major Hurricanes 1920-2017 Source: Judith Curry 2019

 

 

Another factor affecting the Atlantic hurricane season is the El Nino Southern Oscillation (ENSO) cycle. During the cool La Niña phase, westerly winds high in the atmosphere weaken which tend to favor tropical cyclone activity over the North Atlantic.  During the warm El Niño phase, winds increase which suppress Atlantic hurricane activity. 

Currently we are in the cool La Niña phase which should tend to enhance  Atlantic hurricane activity.  If the current trend towards cooler SSTs continues in the Atlantic MDR continues into the peak of the hurricane season, then there will be a dampening effect which could tend to reduce overall Atlantic activity, although with an active  La Niña present, the season could still be above the long-term average.  If, however, the MDR SSTs warm again as they have in recent years then this season could be just as active as the last one.  

Sources:

NOAA National Hurricane Center 

Special Report: Hurricanes and Climate Change, Judith Curry  

Alabama Weather Blog 

Tropical Tidbits  

National Center for Atmospheric Research: Climate Data Guide 

QUALITATIVE DISCUSSION OF ATLANTIC BASIN SEASONAL HURRICANE ACTIVITY FOR 2022,Colorado State University

THE INTERANNUAL VARIABILITY OF HURRICANE ACTIVITY IN THE ATLANTIC AND EAST PACIFIC REGIONS

El Niño & La Niña (El Niño-Southern Oscillation)

 

 

 

 

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