How is PlaneWX different from my EFB or aviationweather.gov?

Your EFB is excellent for charts, filing, and day-of flying. Aviationweather.gov and Flight Service (including 1800WXBRIEF) give you official weather products. PlaneWX sits beside those tools. It does not replace them. What PlaneWX adds is decision support days out: a WX Score matched to your aircraft and personal minimums, a dynamic FRAT on the FAA PAVE framework, and mentors who see the same briefing you see. You can also share a flight plan into PlaneWX from a supported EFB. You stay PIC. Charts, filing, and official sources stay where they belong.

Is the briefing accurate?

Your briefing uses the same official observations and forecasts every pilot relies on: METARs, TAFs, PIREPs, SIGMETs and model guidance. It can only be as accurate as those forecasts, and every forecast carries some uncertainty. Every weather briefing, from any provider, also has the same built-in limit. It describes one departure time, one route, one altitude and one arrival time. Real flights change. You leave late, get rerouted, or get assigned a different altitude, and each change puts you in weather the briefing didn't look at. That's why PlaneWX can keep updating your briefing for monitored flights as the forecast changes, and why your decision-making continues in the air.

How can I make my briefing more accurate?

Enter the flight the way you'll really fly it: a realistic departure time, the route you expect to file or be cleared, your planned altitude, and the right aircraft profile. If any of those change, update the trip and brief again. Check again close to departure, when the forecasts are freshest.

Yes, in specific places. Weather reports, forecasts, model data and NOTAMs are fetched and decoded by code. AI reads forecaster discussions and writes the plain-language briefing, the hazard summary and most section ratings. It also proposes a starting WX Score and some deductions, such as for convection. Ceiling and visibility are always scored by code. Within 12 hours of departure, your personal minimums and aircraft limits are checked by rule-based code, not the AI. Further out, AI also helps weigh icing and turbulence against your limits. You always make the final call.

What is the WX Score?

The WX Score is a 0-100% metric calculated against YOUR personal minimums and your specific aircraft, not generic VFR/IFR categories. It tells you, in a single number, how well conditions are expected to match your standards. Every deduction is transparent and explained.

What is the PAVE framework?

PAVE is the FAA risk framework: Pilot, Aircraft, enVironment, and External pressures. It is the structure behind a serious preflight risk assessment, not a weather product by itself. We walk through it in plain language in our PAVE risk assessment guide. PlaneWX FRAT uses that same framework as a living sit-down assessment near departure. See how PlaneWX FRAT works, including how the briefing and airport context feed the enVironment side.

How far in advance can PlaneWX forecast weather?

PlaneWX provides weather intelligence from 14 days out through departure. Confidence improves as your flight approaches. We are transparent about uncertainty at every time horizon.

What is the mentor system?

PlaneWX connects you with experienced pilots who can review your full briefing (WX Score, aircraft profile, personal minimums) and offer a second set of eyes grounded in shared data, not guesswork. Mentor sits alongside the risk-management loop when you want it.

Is there a free plan?

Yes. Free forever includes full-quality briefings. We limit how much you can use PlaneWX, not how good the analysis is. Details on plans and what each tier includes are in PlaneWX Plans help.

What's the difference between Casual, Pro, and Pro Plus?

Casual is for pilots who fly a few times a month and want auto-monitoring. Pro raises limits and automation. Pro Plus adds Ground Protection, Auto-Brief, Pre-Flight Text, briefed fuel stops, and Labs. Compare current limits and features in Plans help, or start from the pricing section on this page. Personal minimums still drive the WX Score on every plan. If you are setting those for the first time, see personal minimums for weather planning.

What happens after the 14-day free trial?

You keep access on Free, or choose Casual, Pro, or Pro Plus. No card is required to start the trial. Plan details stay in Plans help.

Surface Analysis and Prog Charts for Pilots: Reading the Weather Map

PlaneWX · Last reviewed October 3, 2026

The surface analysis chart is the weather map: an analyzed chart of surface observations that shows sea level pressure with isobars, plus highs, lows, ridges, troughs, fronts, and boundaries such as drylines. The Weather Prediction Center issues those charts for North America eight times daily. Short-range surface prog charts add the forecast: pressure systems, fronts, and precipitation as snapshots at selected valid times over a multiday period. Read analysis for now, prog for what is forecast next, then pair both with the TAF, Area Forecast Discussion, and radar [1, paras. 25.2.3, 25.2.3.1, and 27.10].

Key takeaways

Analysis is the current analyzed pattern. Prog is a forecast snapshot at a stated valid time [1, paras. 25.2.3 and 27.10].
Know the symbols: H/L, troughs, ridges, fronts, drylines, and squall lines [1, Table 25-2 and paras. 27.10.1.3 to 27.10.1.5].
Prog precip colors are chance versus likely probabilities at the valid time, not a guarantee along your route [1, para. 27.10.1.1].

Key facts

A surface analysis chart is an analyzed chart of surface weather observations, commonly called the weather map [1, para. 25.2.3].
WPC surface analysis charts for North America are issued eight times daily (00 through 21 UTC) [1, para. 25.2.3.1].
The chart shows isobars, highs, lows, ridges, troughs, fronts, and boundaries such as drylines [1, para. 25.2.3].
Front symbols show type and point in the direction of motion [1, para. 25.2.2.1.3].
Station plots (station models) summarize temperature, dewpoint, wind, weather, pressure, and sky cover at reporting stations [1, para. 25.2.3.4].
The Unified Surface Analysis Chart is issued four times daily (00, 06, 12, 18 UTC) [1, para. 25.2.4.1].
Short-range surface prog charts forecast pressure systems, fronts, and precipitation for a multiday period as snapshots at selected valid times [1, para. 27.10].
Prog precip uses NDFD chance (25 to less than 55%) and likely (55% or greater) for rain, snow, mix, ice, and thunderstorms [1, para. 27.10.1.1].
Prog charts also depict troughs, drylines, tropical systems, fronts, and squall lines with standard symbols [1, paras. 27.10.1.3 to 27.10.1.5].
Analysis shows the current pattern; prog charts show forecast snapshots. Neither alone is a complete briefing [1, paras. 25.2.3 and 27.10].

Hover, focus, or tap any dotted term for a definition and its official source.

Surface analysis and short-range surface prog charts are how the big picture on the weather map becomes usable for a specific trip. This page stays with Tier 1 FAA definitions from the Aviation Weather Handbook: what the surface analysis chart is, how often it is issued, the analysis symbols, essentials of the station plot, the Unified Surface Analysis Chart, and what short-range surface prog charts forecast. For how fronts, troughs, and drylines behave as weather features (not just as map symbols), use the fronts, troughs, and drylines guide.

What is a surface analysis chart?

“A surface chart (also called surface map or sea level pressure chart) is an analyzed chart of surface weather observations.” “Essentially, a surface chart shows the distribution of sea level pressure (lines of equal pressure are isobars).” The chart also includes highs, lows, ridges, and troughs, plus the location and character of fronts and various boundaries, such as drylines, outflow boundaries, and sea breeze fronts. Pressure is referred to as mean sea level; other elements are as observed at the surface. “A chart in this general form is the one commonly referred to as the weather map.” [1, para. 25.2.3]

“Analysis is the drawing and interpretation of the patterns of various elements on a weather chart.” An isobar is a line connecting points of equal or constant pressure. Contour interval on the NWS Surface Analysis Chart is commonly four millibars [1, paras. 25.2.2 and 25.2.2.1.1].

“The WPC issues surface analysis charts for North America eight times daily, valid at 00, 03, 06, 09, 12, 15, 18, and 21 UTC.” [1, para. 25.2.3.1]

What analysis symbols should you know?

Handbook Table 25-2 defines the core pressure features you will see on the surface chart:

Feature	Definition (Handbook Table 25-2)
Low	A minimum of atmospheric pressure in two dimensions (closed isobars) on a surface chart, or a minimum of height (closed contours) on a constant-pressure chart. Also known as a cyclone. [1, Table 25-2]
High	A maximum of atmospheric pressure in two dimensions (closed isobars) on a surface chart, or a maximum of height (closed contours) on a constant-pressure chart. Also known as an anticyclone. [1, Table 25-2]
Trough	“An elongated area of relatively low atmospheric pressure or height.” [1, Table 25-2]
Ridge	“An elongated area of relatively high atmospheric pressure or height.” May also refer to other quantities such as temperature and dewpoint [1, Table 25-2]

“The symbols on the front indicate the type of front and point in the direction toward which the front is moving.” Two short lines across a front indicate a change in front type [1, para. 25.2.2.1.3]. Drylines and other boundaries also appear on the analysis. This page covers how they are drawn; the weather they produce is on the fronts, troughs, and drylines page.

What does a station plot show?

“Land, ship, buoy, and C-MAN stations are plotted on the chart to aid in analyzing and interpreting the surface weather features.” “These plotted observations are referred to as station models.” Some stations may be omitted for space, but all reporting stations are used in the analysis [1, para. 25.2.3.4]. Essentials of the land station plot (not a full decoder):

Element	How it is plotted
Temperature	Whole degrees Fahrenheit [1, para. 25.2.3.4.2]
Dewpoint	Whole degrees Fahrenheit [1, para. 25.2.3.4.3]
Weather	Symbol if precipitation is occurring or a condition is reducing visibility [1, para. 25.2.3.4.4]
Wind	Increments of 5 kt; stem from the direction the wind is from; flags 50 kt, barbs 10 kt, half-barbs 5 kt; calm is a single circle [1, para. 25.2.3.4.5]
Ceiling	Hundreds of feet AGL [1, para. 25.2.3.4.6]
Visibility	Whole statute miles [1, para. 25.2.3.4.7]
Sea level pressure	Tenths of millibars with the leading 10 or 9 omitted (for example, 103 means 1,010.3 mb) [1, para. 25.2.3.4.8]
Pressure trend	Three-hour change in tenths of millibars plus a symbol for how it changed [1, para. 25.2.3.4.9]
Sky cover	How filled the center circle is [1, para. 25.2.3.4.10]

WPC also produces surface analysis charts aimed at aviation interests with a dedicated station plot model [1, para. 25.2.3.4].

What is the Unified Surface Analysis Chart?

“The NWS Unified Surface Analysis Chart is a surface analysis product produced collectively and collaboratively by the NWS WPC, the OPC, the NHC, and WFO Honolulu.” It analyzes isobars, pressure systems, and fronts, and uses the same analysis symbols as the WPC surface charts. “The Unified Surface Analysis Chart is issued four times daily for valid times 00, 06, 12, and 18 UTC.” [1, paras. 25.2.4, 25.2.4.1, and 25.2.4.2]

What are short-range surface prog charts?

“The NWS WPC provides Short-Range Surface Prog Charts (see Figure 27-24) of surface pressure systems, fronts, and precipitation for a multiday period.” The forecast area covers the CONUS and coastal waters. Forecast conditions are divided into selected valid time periods. “Each chart depicts a ‘snapshot’ of weather elements expected at the specified valid time.” [1, para. 27.10]

“The Short-Range Surface Prog Charts combine WPC forecasts of fronts, isobars, and high/low pressure systems with the NWS’ National Digital Forecast Database (NDFD) digital forecasts from the NWS WFO.” They are issued by the WPC in College Park, MD [1, para. 27.10].

What precipitation and symbols appear on the prog?

Precipitation on the Short-Range Surface Prog Forecast uses NDFD chance and likely categories. Chance means a 25 to less than 55 percent probability of measurable precipitation (or of thunderstorms) at the valid time. Likely means 55 percent or greater [1, para. 27.10.1.1]:

Precip type	Chance (25 to less than 55%)	Likely (55% or greater)
Rain	Light green [1, para. 27.10.1.1]	Dark green [1, para. 27.10.1.1]
Snow	Light blue [1, para. 27.10.1.1]	Dark blue [1, para. 27.10.1.1]
Mix (rain/snow/sleet combinations)	Light purple [1, para. 27.10.1.1]	Dark purple [1, para. 27.10.1.1]
Ice (freezing rain)	Light brown [1, para. 27.10.1.1]	Brown [1, para. 27.10.1.1]
Thunderstorm	Red hatching (chance) [1, para. 27.10.1.1]	Dark red (likely and/or severe) [1, para. 27.10.1.1]

“Pressure systems are depicted by pressure centers, troughs, isobars, drylines, tropical waves, tropical storms, and hurricanes using standard symbols (see Figure 27-25).” “Isobars are denoted by solid, thin black lines and labeled with the appropriate pressure in millibars.” The central pressure is plotted near the center. Fronts and squall lines use the standard symbols on the same legend [1, paras. 27.10.1.3 to 27.10.1.5].

For thunderstorm hazards once convection is in play, use the thunderstorms guide. For how radar fills in the nowcast between chart valid times, use the weather radar guide.

How do pilots use analysis and prog together?

Use the surface analysis for the current analyzed pattern: where the fronts, highs, lows, troughs, and drylines are now, and what nearby station plots are reporting [1, paras. 25.2.3 and 25.2.3.4]. Use the short-range surface prog for forecast snapshots at selected valid times over a multiday period: where those features and precip areas are expected next [1, para. 27.10]. Neither chart sets a go/no-go by itself. Pair them with the TAF change groups, the Area Forecast Discussion for timing confidence, and live radar.

As the PlaneWX glossary puts it, “a TAF says the wind shifts at 18Z, the discussion says it shifts because a cold front arrives and that the forecaster is unsure of the timing.” And “PlaneWX reads the discussion for your airport’s office and quotes it directly.” (Weather & Aviation Glossary) PlaneWX also analyzes WPC discussions: “WPC short-range and extended discussions are analyzed for convective language.” (Hazardous Weather)

In a PlaneWX briefing, Visual mode can show live forecast imagery. The understanding-briefings help notes “Live NOAA/AWC forecast charts embedded per section” (Understanding Your Briefing). The Visual Mode help page covers how prog and related charts are matched to your departure window (Visual Mode).

Where are the official chart references?

Official surface analysis and prog chart references

Links checked October 3, 2026: Handbook PDF anchors resolved from the saved text. AWC prog chart web pages were not used as sources for this draft.

Where do surface charts mislead pilots?

Reading the prog as “now.” A prog is a snapshot at a stated valid time over a multiday forecast period, not a live observation [1, para. 27.10].
Treating chance precip as a lock. Chance means 25 to less than 55 percent at the valid time; likely is 55 percent or greater. Neither is a guarantee on your route [1, para. 27.10.1.1].
Timing from the front symbol alone. The symbol shows type and direction of motion, not the hour it hits your airport [1, para. 25.2.2.1.3]. Pair the chart with the TAF and AFD.
Ignoring station plots near the route. The analysis draws the pattern; nearby plots tell you temperature, wind, weather, and pressure trend at the surface [1, para. 25.2.3.4].
Stopping at the map. Thunderstorm and radar products still matter once convection is drawn or developing [1, paras. 27.10.1.1 and 27.10.1.5].

How do you use these charts in a go/no-go decision?

The decision is yours as PIC. Habits drawn from the Handbook guidance above:

Start with the analysis. Locate the fronts, highs, lows, troughs, and drylines relative to your route [1, para. 25.2.3].
Check issuance and valid time. Surface analysis is eight times daily; Unified is four times daily; prog panels are snapshots at selected valid times [1, paras. 25.2.3.1, 25.2.4.1, and 27.10].
Read prog precip as probability bands. Chance versus likely, and rain versus snow versus mix versus ice versus thunderstorms [1, para. 27.10.1.1].
Confirm with AFD and TAF. When the forecaster is unsure of frontal timing, build more margin [2].
If thunderstorms or squall lines are drawn, use the thunderstorm playbook. Map symbols flag the threat; avoidance and product timing live on the thunderstorms page [1, para. 27.10.1.5].

Where do these charts fit in a disciplined decision?

PlaneWX is decision support for general aviation pilots, built around one idea: “Fly like it’s your job.” Treat the weather decision the way a professional crew would, with the same process every time. That process is a loop: WX Score, then FRAT, then GO / NO-GO, then Self Debrief, with a Mentor if you want one. Synoptic charts and discussions feed the WX Score and the briefing narrative. Here’s how PlaneWX handles them, as its help center describes [2]:

WX Score and AFD. “PlaneWX reads the discussion for your airport’s office and quotes it directly.” (Weather & Aviation Glossary)
WX Score and WPC discussions. “WPC short-range and extended discussions are analyzed for convective language.” (Hazardous Weather)
Visual briefing charts. “Live NOAA/AWC forecast charts embedded per section” (Understanding Your Briefing), with Visual Mode details at Visual Mode.
FRAT. The flight risk assessment opens in the last 4 hours before departure (FRAT).
GO / NO-GO. “PlaneWX never recommends GO or NO-GO. You make the call as PIC.” (The Risk Loop)
Self Debrief. If a front or precip area arrived earlier or later than the analysis and prog suggested, note it for the next trip (The Risk Loop).

The help center is plain about the limits: “PlaneWX is not a substitute for a complete, independent pre-flight weather briefing. Pull one from a source you already trust before you fly.” (The Risk Loop)

Check the surface pattern and discussions on your route in a PlaneWX briefing, or read how Visual mode shows forecast charts.

Frequently asked questions

What is a surface analysis chart?

“A surface chart (also called surface map or sea level pressure chart) is an analyzed chart of surface weather observations.” It shows sea level pressure with isobars, plus highs, lows, ridges, troughs, fronts, and boundaries such as drylines [1, para. 25.2.3].

How often is the surface analysis chart issued?

“The WPC issues surface analysis charts for North America eight times daily, valid at 00, 03, 06, 09, 12, 15, 18, and 21 UTC.” [1, para. 25.2.3.1]

What do the front symbols mean?

“The symbols on the front indicate the type of front and point in the direction toward which the front is moving.” Two short lines across a front mark a change in front type [1, para. 25.2.2.1.3]. Feature weather (warm/cold/stationary/occluded, troughs, drylines) is covered on the fronts, troughs, and drylines page.

What is a station plot?

Plotted surface observations on the chart are called station models. They summarize temperature, dewpoint, wind, weather, pressure, sky cover, and related elements at that station [1, para. 25.2.3.4].

What is the Unified Surface Analysis Chart?

“The NWS Unified Surface Analysis Chart is a surface analysis product produced collectively and collaboratively by the NWS WPC, the OPC, the NHC, and WFO Honolulu.” “The Unified Surface Analysis Chart is issued four times daily for valid times 00, 06, 12, and 18 UTC.” [1, paras. 25.2.4 and 25.2.4.1]

What is a short-range surface prog chart?

“The NWS WPC provides Short-Range Surface Prog Charts (see Figure 27-24) of surface pressure systems, fronts, and precipitation for a multiday period.” “Each chart depicts a ‘snapshot’ of weather elements expected at the specified valid time.” [1, para. 27.10]

What precipitation does the prog chart show?

NDFD rain, snow, mix, ice, and thunderstorm areas as chance (25 to less than 55 percent) or likely (55 percent or greater) of measurable precipitation (or thunderstorms) at the valid time [1, para. 27.10.1.1].

What else is on the prog chart besides precip?

Pressure centers, troughs, isobars, drylines, tropical waves, tropical storms, and hurricanes; fronts; and squall lines, using standard symbols [1, paras. 27.10.1.3 to 27.10.1.5].

How should pilots use analysis and prog together?

Use the surface analysis for the current analyzed pattern (where the fronts and pressure systems are now). Use the short-range surface prog for forecast snapshots at selected valid times over a multiday period. Pair both with the TAF, Area Forecast Discussion, and radar, not as a standalone go/no-go [1, paras. 25.2.3 and 27.10].

Does PlaneWX tell me to GO or NO-GO from a prog chart?

“PlaneWX never recommends GO or NO-GO. You make the call as PIC.” Briefings can quote the Area Forecast Discussion and analyze WPC discussions for convective language; Visual mode can show live NOAA/AWC forecast charts [2].

Glossary

Every term below links to the FAA, NWS, or NOAA document that defines it. The same definitions appear when you hover, focus, or tap a dotted term on this page.

Dryline: A low-level boundary, hundreds of miles long, separating moist air from dry air; a common trigger for severe storms on the High Plains. Source: FAA Aviation Weather Handbook, 11.5
Front: A boundary or transition zone between two air masses, where most weather happens. Source: FAA Aviation Weather Handbook, 11.3
Isobar: A line on a chart connecting points of equal pressure. Source: FAA Aviation Weather Handbook, Table 25-1
Ridge: An elongated area of relatively high atmospheric pressure or height. Source: FAA Aviation Weather Handbook, Table 25-2
Short-range surface prog chart: A WPC forecast chart of surface pressure systems, fronts, and precipitation for selected valid times over a multiday period. Source: FAA Aviation Weather Handbook, 27.10
Station plot: A plotted surface observation on the analysis chart showing temperature, dewpoint, wind, weather, pressure, sky cover, and related elements at that station. Source: FAA Aviation Weather Handbook, 25.2.3.4
Surface analysis chart: An analyzed chart of surface weather observations showing sea level pressure with isobars, plus highs, lows, ridges, troughs, fronts, and boundaries such as drylines. Source: FAA Aviation Weather Handbook, 25.2.3
Trough: An elongated area of relatively low atmospheric pressure or height. Source: FAA Aviation Weather Handbook, Table 25-2

This page explains published FAA guidance. It is not a substitute for a current weather briefing or for instrument training. Always get a current briefing before you fly. PlaneWX never recommends GO or NO-GO; you make the call as PIC.

References

FAA‑H‑8083‑28B, “Aviation Weather Handbook.” Federal Aviation Administration, Flight Standards Service. April 2, 2026. Paragraphs cited: 25.2.2 to 25.2.4, Table 25-1, Table 25-2, 27.10 to 27.10.1.5. https://www.faa.gov/regulationspolicies/handbooksmanuals/aviation/faa-h-8083-28b-aviation-weather-handbook. PDF: https://www.faa.gov/sites/faa.gov/files/FAA-H-8083-28B.pdf
PlaneWX Help Center: “Weather & Aviation Glossary,” “Hazardous Weather,” “Understanding Your Briefing,” “Visual Mode,” “FRAT,” “The Risk Loop.” PlaneWX. Accessed October 3, 2026. Weather & Aviation Glossary · Hazardous Weather · Understanding Your Briefing · Visual Mode · FRAT · The Risk Loop