000 AXPZ20 KNHC 061601 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Feb 6 2017 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ axis extends from 02N90W to 02N100W to 03N108W to 02N117W to 02N125W. It is bisected by a trough that extends from 09N134W to 03N135W, and resumes at 02N137W to just beyond 01N140W. Scattered moderate isolated strong convection is noted within 120 nm south of the axis between 105W and 109W. Scattered moderate convection is within 60 nm south of the axis between 110W and 112W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A tight pressure gradient over southeastern Mexico, and just inland the Isthmus of Tehuantepec is supporting a swath of fresh to strong north to northeast winds north of 14N between 94W and 96W including the Gulf of Tehuantepec region. Latest model guidance shows the tight pressure slackening during the course of the morning and early afternoon. This will allow for the the fresh to strong north to northeast winds to become mainly moderate north winds this afternoon. These winds will continue to diminish through tonight, and become gentle west to northwest by Wednesday evening. The model guidance of suggests that the next Gulf of Tehuantepec gap wind event, with gale conditions possible, is expected late Thursday night as strong high pressure builds southward across the Gulf of Mexico in the wake of a cold front. High pressure of 1019 mb centered near 26N121W extends a ridge southeastward to near the Revillagigedo Islands. The pressure gradient between the ridge, and weak troughing over the Gulf of California is supporting gentle to moderate northerly winds off the west coast of the Baja California peninsula. Seas in this area are in the 5-6 ft range. Light to gentle winds and seas 2 ft or less prevail over the Gulf of California, while gentle to moderate winds and seas 4-6 ft prevail off the southwest coast of Mexico. The 1019 mb high is forecast to remain nearly stationary through Tuesday, but strengthen slightly. It is then forecast to lift northward to near 32N122W by Wednesday afternoon. As this takes place, the pressure gradient between the associated ridging and the trough over the Gulf of California will tighten some allowing for fresh to locally strong northwest winds to materialize off the west coast of the Baja California peninsula as well as portions of the Gulf of California Tuesday night and Wednesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient between high pressure over the southeastern United States, and lower pressures south of 10N in the eastern Pacific is bringing fresh to strong northeast to east winds through the Gulf of Papagayo, and westward to near 89W from 10N to 12N with seas of 5-8 ft. The area of high pressure will shift eastward over the next couple of days. This initiated a weakening of the culprit pressure gradient. The fresh to strong northeast winds will respond by diminishing to mostly fresh, but pulse to strong on Wednesday as the pressure gradient fluctuates to at times a tighter gradient. Strong north winds through the Gulf of Panama are forecast to diminish to fresh this morning, then pulse from moderate to fresh through Wednesday. Otherwise, light and variable winds and 4-6 ft seas will prevail elsewhere throughout this portion of the discussion area. REMAINDER OF THE AREA... A ridge, associated with the aforementioned high pressure of 1019 mb continues to dominate the northern waters. Long period NW swell propagating through the northwest portion of the area is producing seas in the range of 8-12 ft range there. This swell train with a leading edge period of 17 to 18 seconds will reach from Los Cabos to the Equator at 129W this evening, the Revillagigedo Islands late tonight into Tuesday morning, and to near 100W on Wednesday. A tight pressure gradient between the aforementioned high pressure center of 1019 mb and lower pressure in the vicinity of the ITCZ associated with a trough analyzed from near 09N134W to 03N125W is supporting an area of fresh to strong northeast trades west of the trough from 06N to 11N with resultant seas in the 8-10 ft range. Otherwise, moderate to fresh trades are present north of the ITCZ to near 16N elsewhere west of 120W. The gradient west of the trough is forecast to weaken through Wednesday. This will allow for the fresh to strong northeast winds to diminish to the fresh range from 06N to 14N between 116W and 135W with seas of 8 ft in a NW swell. The upper pattern is becoming quite progressive with time over the NW portion of the area. A series of deep low pressure centers with attendant cold fronts will approach the NW portion through Wednesday. The first of the lows, a 984 mb low well northwest of the area, has an associated cold front stretching southwestward to 32N146W and continuing well to the southwest to the northwest section of the Hawaiian Islands. The tight pressure gradient between this front and the high pressure situated over the discussion waters, as discussed earlier in the discussion, is forecast to initiated strong southwest winds to the northwest of a line from 32N137W to 28N140W early this evening with seas building 8-12 ft in long period NW swell. These seas will gradually build to 12-15 ft by early Wednesday as the southwest winds increase to near gale force, or even possibly gale force to the northwest of a line roughly from 32N136W to 27N140W. Also by early on Wednesday, global model guidance depicts a stronger cold front than the one currently west of the area near 146W to be connected to deepening low pressure, deeper than the previously mentioned 984 mb one, that will pass well to the northwest of the area. This low will drive the stronger cold front to just west of the northwest corner of the area at that time. The front will then move across the northwest waters during Wednesday followed by an extensive area of large seas that be steered into these waters via another batch of large W to NW swell. The front presently west of the area that crosses 32N at 146W will weaken as it approaches the far northwest corner late tonight. $$ AGUIRRE