000 AXPZ20 KNHC 122157 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Jun 12 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...SPECIAL FEATURES... Recently upgraded Tropical Storm Calvin is centered near 15.5N 95.5W or 65 nm east-southeast of Puerto Angel Mexico at 12/2100 UTC moving west-northwest, or 300 degrees, at 2 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Latest visible satellite imagery shows that overall cloud pattern around the cyclone has become symmetrical around a small well-defined center of circulation during the afternoon. Latest satellite imagery shows large convective bursts of scattered strong convection within 90 nm of the center in the southwest quadrant, and elsewhere within 60 nm of the center. Scattered moderate isolated strong convection is noted elsewhere within 150 nm of the center in the southern semicircle, also within 30 nm of a line from 15N97W to 16N99W and within 30 nm of another line from 16N99W to 16N101W. Calvin is forecast to maintain intensity as it moves to near 15.8N 96.0W late tonight, then weaken to a depression just inland the Mexican coast near 16.0N 96.5W Tuesday afternoon. It is forecast to weaken further to a post-tropical/remnant low near 16.2N 97.0W late Tuesday night. The main issue with this tropical cyclone will be heavy rainfall that it will bring across portions of southeastern Mexico and Guatemala. These rains may lead to life- threatening flash floods and mudslides. See the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPEP3/WTPZ33 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCMEP3/WTPZ23 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Monsoon Trough axis extends from 10N84W to 14N91W. It then resumes from 14N98W to 09N109W to 08N118W, where scatterometer winds suggest that that the ITCZ extends then resumes to 07N126W to 09.5N133.5W. Scattered moderate isolated strong convection is noted over the far eastern portion of the area south of the axis from 04N to 09N between 80W and 84W. Scattered moderate convection is observed within 120 nm south of the axis between 100W and 104W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on Tropical Depression Three-E. Outside Tropical Storm Calvin, fresh to locally strong northwest winds with seas reaching to 9 ft are present offshore the coast of Baja California Norte. Moderate to fresh winds prevail over the far northern Gulf of California, light to gentle winds over the remainder of the Gulf of California, and gentle to moderate winds elsewhere over the open waters off the coast of Mexico. The fresh to locally strong fresh northwest winds will diminish to mainly fresh winds on Tuesday, and become moderate to fresh winds on Wednesday. The northwest swell propagating through those waters will gradually subside through Wednesday, with seas lowering to mostly below 8 ft, except over the far northwest corner of the 250 nm range from Mexico. Looking ahead toward the middle of the week and into next weekend...there is the potential for a significant heavy rain event across portions of Central America and southern Mexico. A large cyclonic gyre is forecast to begin to develop around Wednesday and through the end of the week. Models indicate that it will move slowly across the northern portion of Central America and southern Mexico. Abundant tropical moisture will be advected across Central America and southern Mexico, with the potential for heavy rainfall producing life-threatening flash floods and mudslides. Will continue to monitor this evolving weather pattern during the next couple days and provide updates. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see above for the potential of heavy rainfall across the portions of Central America later this week. Elsewhere...gentle to moderate westerly winds and 4 to 6 ft seas are expected north of 07N...and gentle to moderate southwest to west winds with 5 to 7 ft seas are forecast to the south of 07N through Wednesday. Winds will increase over the northern zones as a large cyclonic gyre develops over Central America. REMAINDER OF THE AREA... A high pressure ridge axis extends from 32N133W southeastward to near 25N120W. High pressure covers the area north of 15N. A rather well-defined surface trough is analyzed from 14N136W to 05N136W, moving westward near 12 kt. Satellite imagery shows scattered moderate to strong convection within 240 nm east of the trough from 08N to 12N. Scattered moderate convection is east of the trough within 30 nm of a line from 06N134W to 08N130W. There is a locally tighter pressure gradient between the trough and ridge axis resulting in mainly fresh northeast winds north of the trough. This will continue as the trough shifts westward during the next couple of days. Outside the trough, the analyzed pressure gradient supports moderate to fresh winds along with seas in the 4 to 6 ft range. $$ Aguirre