Environmental Overview: Amber/Amberland Coast Monthly Climatology March, April, May This brief is intended for METOC personnel. It is not designed as a one-size fits all for every echelon. Each unit must tailor this brief to their own specific requirements. UNCLASSIFIED II-D-1 (U) BOLD ALLIGATOR 13 EXERCISE DIRECTIVE 05 Oct 2012 PART II, Section D: ENVIRONMENTAL OVERVIEW

Seasonal Discussion for March The Coral High shows considerable development and spreads slightly northward of its February position. Consequently, the outbreaks of polar air along the Treasure Coast are less frequent, with about 1/3 less Polar Fronts reaching Coral. The increase of moist air overriding polar air over this area is conducive to waves developing on the Polar Front lying offshore. Intense highs and lows are common in March. When a high is centered over northeastern Sapphire, the local area is dominated by clear skies, cool temperatures, and northeasterly winds for several days at a time. On the other hand, this area may be characterized by strong, fast-moving cold fronts, with waves still developing in the Western Gulf of Garnet. The center of waves developing on the Polar Front in the Western Gulf of Garnet move to the northeast along the coast, passing out to sea near the central Amberland coast. These waves reach this area in hours. As they approach from the southwest, the rain shield will extend miles ahead of the center, with strong northeasterly winds. The result of an approaching wave may cause rain to fall at this station for at least hours without stopping. Thunderstorms occasionally will occur with these waves, or the passage of a front. Thunderstorms are considered to be few in number in March, and air mass thunderstorms seldom occur. Yet, just off shore, thunderstorm activity is on the increase due to the Eastern Gulf of Garnet Stream’s effect on fronts moving offshore. Any snowfall that occurs is usually associated with frontal waves that move across the southern Treasure Coast countries, approaching this area from the west-southwest, moving offshore just south of the area. Fog and ground fog occur often, but less than February. Flying conditions are generally good. UNCLASSIFIED II-D-2

Amber/Amberland Coast - March STATISTICSWINDSSKY CONDITION BKN/OVC 55 % N S SW 8 kts W E RAIN SNOW BS/BD TSTM FOG DAYS DAY DAYS RH 79% (0700L) RH 52% (1600L) Potential Impacts: -Winds less than 11 kts occur 72% of the time -Winds kts occur <.5% of the time -Visibility less than 5 NM occurs 11% of the time -Ceilings less than 1,000 ft and/or visibility less than 5 NM occur 15% of the time -Ceilings less than 300 ft and/or visibility less than 1 NM occur 3% of the time PRECIPITATION Monthly Mean TEMPERATURE MAX MIN 65°F 43°F 100°F 90°F 80°F 70°F 60°F 50°F 40°F 30°F 20°F EXTREME HIGH: EXTREME LOW: 92°F 12°F EXTREME HIGH: EXTREME LOW: 8.0” 0.8” Mean: 4.0” TEMPERATURE Avg MAX Avg MIN Worldwide Surface Climate Summaries Version 1.0 UNCLASSIFIED II-D-3

1000 mb Heights (m)/Winds (kts) - March NCEP UNCLASSIFIED II-D-4

850 mb Heights (m)/Winds (kts) - March NCEP UNCLASSIFIED II-D-5

700 mb Heights (m)/Winds (kts) - March NCEP UNCLASSIFIED II-D-6

500 mb Heights (m)/Winds (kts) - March NCEP UNCLASSIFIED II-D-7

250 mb Heights (m)/Winds (kts) - March NCEP UNCLASSIFIED II-D-8

Seasonal Discussion for April The Coral High is displaced a few degrees north of its March position. It is well on its journey northward for the summer. The Eastern Sapphirian Low, in the same turn, starts to weaken and move northward. Cold frontal passages are about the same as in March, except the outbreaks of cold air from Sapphire grow less frequent toward the end of the month. At least one wave will develop on the Polar Front in the Western Gulf of Garnet area and move northeastward along the front. During the first part of the month, the winds are still gusty from the north-northwest, however, the frequency of winds flowing from a southerly direction is increasing. April boasts the lowest mean humidity for the year. Air mass thunderstorms are on the increase, and occur almost three times as often as in March. Thunderstorms are often associated with frontal passages and intensify out over the Eastern Gulf of Garnet Stream, but on the whole, stormy weather offshore is not as great as in March, and does not last long. Fog is still common with a light northeasterly wind. Flying conditions are outstanding. UNCLASSIFIED II-D-9

Amber/Amberland Coast - April STATISTICSWINDSSKY CONDITION BKN/OVC 51 % N S SSW 8 kts W E RAIN SNOW BS/BD TSTM FOG DAYS DAY DAYS 11 < RH 79% (0700L) RH 49% (1600L) Potential Impacts: -Winds less than 11 kts occur 74% of the time -Winds kts occur <.5% of the time -Visibility less than 5 NM occurs 6% of the time -Ceilings less than 1,000 ft and/or visibility less than 5 NM occur 8% of the time -Ceilings less than 300 ft and/or visibility less than 1 NM occur 1% of the time PRECIPITATION Monthly Mean TEMPERATURE MAX MIN 74°F 51°F 100°F 90°F 80°F 70°F 60°F 50°F 40°F 30°F 20°F EXTREME HIGH: EXTREME LOW: 95°F 26°F EXTREME HIGH: EXTREME LOW: 8.8” 0.1” Mean: 2.9” TEMPERATURE Avg MAX Avg MIN Worldwide Surface Climate Summaries Version 1.0 UNCLASSIFIED II-D-10

1000 mb Heights (m)/Winds (kts) - April NCEP UNCLASSIFIED II-D-11

850 mb Heights (m)/Winds (kts) - April NCEP UNCLASSIFIED II-D-12

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250 mb Heights (m)/Winds (kts) - April NCEP UNCLASSIFIED II-D-15

Seasonal Discussion for May The Coral High continues to build northward, as the Eastern Sapphirian Low weakens. Otherwise, the pressure pattern remains the same as in April. Offshore weather is generally good as a whole, but thunderstorms and showers increase as fronts pass through, and out over the Eastern Gulf of Garnet Stream. Fronts tend to be oriented more east-west and often seem to remain stationary just to the north, with warm tropical air flowing over the region for several days. The frequency of cold frontal passage is less than in April. Thunderstorm activity is still on an increase occurring with frontal activity and air masses, the reason being that, any wedge of cold air moving into this area will lift the tropical air causing convective type weather. Precipitation is greater than in April; it has increased to a monthly mean of 4.0 inches. Fog is also on the increase, occurring with a well defined gradient flow from the northeast after the passage of a frontal system. Fog and ground fog also occur with a very light southerly flow because of warmer air flowing from the Eastern Gulf of Garnet Stream across cooler water, and inland over the area. Flying weather is very good. UNCLASSIFIED II-D-16

Amber/Amberland Coast - May STATISTICSWINDSSKY CONDITION BKN/OVC 58 % N S S 7 kts W E RAIN SNOW BS/BD TSTM FOG DAYS RH 82% (0700L) RH 56% (1600L) Potential Impacts: -Winds less than 11 kts occur 80% of the time -Winds kts occur <.5% of the time -Visibility less than 5 NM occurs 9% of the time -Ceilings less than 1,000 ft and/or visibility less than 5 NM occur 11% of the time -Ceilings less than 300 ft and/or visibility less than 1 NM occur 1% of the time PRECIPITATION Monthly Mean TEMPERATURE MAX MIN 80°F 60°F 100°F 90°F 80°F 70°F 60°F 50°F 40°F 30°F 20°F EXTREME HIGH: EXTREME LOW: 98°F 33°F EXTREME HIGH: EXTREME LOW: 8.4” 0.6” Mean: 3.9” TEMPERATURE Avg MAX Avg MIN Worldwide Surface Climate Summaries Version 1.0 UNCLASSIFIED II-D-17

1000 mb Heights (m)/Winds (kts) - May NCEP UNCLASSIFIED II-D-18

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500 mb Heights (m)/Winds (kts) - May NCEP UNCLASSIFIED II-D-21

250 mb Heights (m)/Winds (kts) - May NCEP UNCLASSIFIED II-D-22