Below is a list of some products I'm using for a client's weather prediction services

Tropical cyclone monitoring

• Tropical cyclone forecast tools
• Joint Typhoon Warning Center
• Japan Meteorological Agency

U.S. Weather

• US weather analysis tools
• Models
• Model Output Statistics (MOS) and National Blend of Models (NBM)
• Miscellaneous forecast tools

U.S. Severe Weather

• Storm Prediction Center
• HRRR model
• NAM model (3 km)
• NAM model (12 km)
• Live US radar
• Archive US radar

U.S. Winter weather guidance

• NOAA's WPC winter weather website
• NOAA's WPC winter precipitation website
• NOAA's snow analyses

U.S. Aviation Weather

• Aviation Weather Center
• INSITE   (COMET module on INSITE is here)

International weather maps

• Europe weather maps --- analysis and forecast (courtesy of Free University of Berlin's Dept of Geoscience)
• Great Britain forecast charts (from UKMET)
• West Pacific forecast charts (courtesy Hong Kong Observatory)
• Asia weather charts (courtesy Thai Meteorological Department)
• Spain (courtesy State Meteorological Agency - AEMET - Spanish Government)
• General website: Meteologix

International weather warnings

• Europe (meteoalarm website)
• WMO Severe Weather Information Centre ; link to beta version
• United Arab Emirates
• China
• Switzerland
• Russia
• Germany
• Italy
• Singapore heavy rain warnings
• Spain

Forecast discussions for US sites of interest

• Andrews AFB, MD
• Appleton, WI
• Bedford, MA
• Beverly Hills, CA
• Brunswick, GA
• Dallas, TX
• El Centro, CA (close to Mexicali)
• Fort Lauderdale, FL
• Fort Smith, AR
• Hayward, CA
• Honolulu, HI
• Huntsville, AL
• Houston, TX  area (IAH and Hobby)
• Lakeland, FL
• Las Vegas, NV
• Lincoln, CA
• Long Beach, CA
• Manhattan, NY
• Point Mugu, CA
• Saint Louis, MO
• Savannah, GA
• Seattle, WA
• Tampa, FL (Macdill AFB)
• Teterboro, NJ
• Tulsa, OK
• Van Nuys, CA
• Washington, DC area (Reagan National Airport, Dulles Airport, metro)
• Waukegan, IL
• West Palm Beach, FL
• Westfield, MA

Time series for US sites of interest

• Andrews AFB, MD
• Appleton International Airport, WI
• Bedford, MA (Hanscom AFB)
• Beverly Hills, CA
• Brunswick Golden Isles Airport, GA
• Dallas Love Field, TX
• El Centro, CA (close to Mexicali)
• Fort Lauderdale-Hollywood International Airport, FL
• Fort Smith Regional Airport, AR
• Hayward Executive Airport, CA
• Honolulu, HI
• Huntsville International Airport, AL
• Houston International Airport, TX
• Houston Hobby Airport, TX
• Lakeland Linder Regional Airport, FL
• Las Vegas, NV (McCarran International Airport)
• Lincoln Regional Airport, CA
• Long Beach, CA
• Manhattan, NY
• Point Mugu, CA
• Saint Louis Downtown Airport, MO
• Savannah International Airport, GA
• Seattle-Tacoma International Airport, WA
• Tampa (Macdill AFB), FL
• Teterboro Airport, NJ
• Tulsa International Airport, OK
• Van Nuys Airport, CA
• Washington, DC (Reagan National Airport)
• Washington, DC (Dulles airport)
• Waukegan Regional Airport, IL
• West Palm Beach - Palm Beach International Airport, FL
• Westfield-Barnes Regional Airport, MA

Forecast discussions for international sites of interest

• Athens, Greece
• Bangkok, Thailand
• Beijing, China
• Calexico, CA (proxy for Mexicali)
• Dubai, United Arab Emirates
• Geneva, Switzerland
• Hong Kong
• Kiev, Ukraine
• Moscow, Russia
• Paris and Nice, France
• Ramstein Air Base, Germany
• Italy
• Singapore
• Sorocaba, Brazil
• United Kingdom
• Valencia, Spain

Time series for international sites of interest​

• Athens, Greece
• Bangkok, Thailand
• Beijing, China
• Calexico, CA (proxy for Mexicali)
• Dubai, United Arab Emirates
• Farmborough, UK  Also try this link:
• Geneva, Switzerland
• Heathrow, UK
• Hong Kong
• Kiev, Ukraine
• ​London
• Moscow, Russia
• Nice, France
• Paris, France
• Ramstein Air Base, Germany
• Sigonella, Italy
• Singapore (Marina Bay): 24-hour and four day. Here is a more detailed forecast courtesy of the Norwegian Meteorological Insitute.
• Sorocaba, Brazil (scroll down the list)
• United Kingdom 
• Valencia, Spain: Here is some model output.